diff --git a/.changeset/sixty-mice-sleep.md b/.changeset/sixty-mice-sleep.md
new file mode 100644
index 0000000000000..ef821a610ee07
--- /dev/null
+++ b/.changeset/sixty-mice-sleep.md
@@ -0,0 +1,5 @@
+---
+"@medusajs/types": patch
+---
+
+feat(cart): Shipping method adjustments
diff --git a/packages/cart/integration-tests/__tests__/services/cart-module/index.spec.ts b/packages/cart/integration-tests/__tests__/services/cart-module/index.spec.ts
index 0e467ce23ea6c..d07367ecb1523 100644
--- a/packages/cart/integration-tests/__tests__/services/cart-module/index.spec.ts
+++ b/packages/cart/integration-tests/__tests__/services/cart-module/index.spec.ts
@@ -1005,6 +1005,7 @@ describe("Cart Module Service", () => {
       await service.setLineItemAdjustments(createdCart.id, [
         {
           id: adjustments[0].id,
+          item_id: itemOne.id,
           amount: 50,
           code: "50%",
         },
@@ -1310,4 +1311,553 @@ describe("Cart Module Service", () => {
       expect(adjustments?.length).toBe(0)
     })
   })
+
+  describe("setShippingMethodAdjustments", () => {
+    it("should set shipping method adjustments for a cart", async () => {
+      const [createdCart] = await service.create([
+        {
+          currency_code: "eur",
+        },
+      ])
+
+      const [shippingMethodOne] = await service.addShippingMethods(
+        createdCart.id,
+        [
+          {
+            amount: 100,
+            name: "test",
+          },
+        ]
+      )
+
+      const [shippingMethodTwo] = await service.addShippingMethods(
+        createdCart.id,
+        [
+          {
+            amount: 200,
+            name: "test-2",
+          },
+        ]
+      )
+
+      const adjustments = await service.setShippingMethodAdjustments(
+        createdCart.id,
+        [
+          {
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          },
+          {
+            shipping_method_id: shippingMethodTwo.id,
+            amount: 200,
+            code: "FREE-2",
+          },
+        ]
+      )
+
+      expect(adjustments).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          }),
+          expect.objectContaining({
+            shipping_method_id: shippingMethodTwo.id,
+            amount: 200,
+            code: "FREE-2",
+          }),
+        ])
+      )
+    })
+
+    it("should replace shipping method adjustments for a cart", async () => {
+      const [createdCart] = await service.create([
+        {
+          currency_code: "eur",
+        },
+      ])
+
+      const [shippingMethodOne] = await service.addShippingMethods(
+        createdCart.id,
+        [
+          {
+            amount: 100,
+            name: "test",
+          },
+        ]
+      )
+
+      const adjustments = await service.setShippingMethodAdjustments(
+        createdCart.id,
+        [
+          {
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          },
+        ]
+      )
+
+      expect(adjustments).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          }),
+        ])
+      )
+
+      await service.setShippingMethodAdjustments(createdCart.id, [
+        {
+          shipping_method_id: shippingMethodOne.id,
+          amount: 50,
+          code: "50%",
+        },
+      ])
+
+      const cart = await service.retrieve(createdCart.id, {
+        relations: ["shipping_methods.adjustments"],
+      })
+
+      expect(cart.shipping_methods).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            id: shippingMethodOne.id,
+            cart_id: createdCart.id,
+            adjustments: expect.arrayContaining([
+              expect.objectContaining({
+                shipping_method_id: shippingMethodOne.id,
+                amount: 50,
+                code: "50%",
+              }),
+            ]),
+          }),
+        ])
+      )
+
+      expect(cart.shipping_methods?.length).toBe(1)
+      expect(cart.shipping_methods?.[0].adjustments?.length).toBe(1)
+    })
+
+    it("should remove all shipping method adjustments for a cart", async () => {
+      const [createdCart] = await service.create([
+        {
+          currency_code: "eur",
+        },
+      ])
+
+      const [shippingMethodOne] = await service.addShippingMethods(
+        createdCart.id,
+        [
+          {
+            amount: 100,
+            name: "test",
+          },
+        ]
+      )
+
+      const adjustments = await service.setShippingMethodAdjustments(
+        createdCart.id,
+        [
+          {
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          },
+        ]
+      )
+
+      expect(adjustments).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          }),
+        ])
+      )
+
+      await service.setShippingMethodAdjustments(createdCart.id, [])
+
+      const cart = await service.retrieve(createdCart.id, {
+        relations: ["shipping_methods.adjustments"],
+      })
+
+      expect(cart.shipping_methods).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            id: shippingMethodOne.id,
+            adjustments: [],
+          }),
+        ])
+      )
+
+      expect(cart.shipping_methods?.length).toBe(1)
+      expect(cart.shipping_methods?.[0].adjustments?.length).toBe(0)
+    })
+
+    it("should update shipping method adjustments for a cart", async () => {
+      const [createdCart] = await service.create([
+        {
+          currency_code: "eur",
+        },
+      ])
+
+      const [shippingMethodOne] = await service.addShippingMethods(
+        createdCart.id,
+        [
+          {
+            amount: 100,
+            name: "test",
+          },
+        ]
+      )
+
+      const adjustments = await service.setShippingMethodAdjustments(
+        createdCart.id,
+        [
+          {
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          },
+        ]
+      )
+
+      expect(adjustments).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          }),
+        ])
+      )
+
+      await service.setShippingMethodAdjustments(createdCart.id, [
+        {
+          id: adjustments[0].id,
+          amount: 50,
+          code: "50%",
+        },
+      ])
+
+      const cart = await service.retrieve(createdCart.id, {
+        relations: ["shipping_methods.adjustments"],
+      })
+
+      expect(cart.shipping_methods).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            id: shippingMethodOne.id,
+            adjustments: [
+              expect.objectContaining({
+                id: adjustments[0].id,
+                shipping_method_id: shippingMethodOne.id,
+                amount: 50,
+                code: "50%",
+              }),
+            ],
+          }),
+        ])
+      )
+
+      expect(cart.shipping_methods?.length).toBe(1)
+      expect(cart.shipping_methods?.[0].adjustments?.length).toBe(1)
+    })
+  })
+
+  describe("addShippingMethodAdjustments", () => {
+    it("should add shipping method adjustments in a cart", async () => {
+      const [createdCart] = await service.create([
+        {
+          currency_code: "eur",
+        },
+      ])
+
+      const [shippingMethodOne] = await service.addShippingMethods(
+        createdCart.id,
+        [
+          {
+            amount: 100,
+            name: "test",
+          },
+        ]
+      )
+
+      const adjustments = await service.addShippingMethodAdjustments(
+        createdCart.id,
+        [
+          {
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          },
+        ]
+      )
+
+      expect(adjustments).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          }),
+        ])
+      )
+    })
+
+    it("should add multiple shipping method adjustments for multiple shipping methods", async () => {
+      const [createdCart] = await service.create([
+        {
+          currency_code: "eur",
+        },
+      ])
+
+      const [shippingMethodOne] = await service.addShippingMethods(
+        createdCart.id,
+        [
+          {
+            amount: 100,
+            name: "test",
+          },
+        ]
+      )
+      const [shippingMethodTwo] = await service.addShippingMethods(
+        createdCart.id,
+        [
+          {
+            amount: 200,
+            name: "test-2",
+          },
+        ]
+      )
+
+      const adjustments = await service.addShippingMethodAdjustments(
+        createdCart.id,
+        [
+          {
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          },
+          {
+            shipping_method_id: shippingMethodTwo.id,
+            amount: 150,
+            code: "CODE-2",
+          },
+        ]
+      )
+
+      expect(adjustments).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          }),
+          expect.objectContaining({
+            shipping_method_id: shippingMethodTwo.id,
+            amount: 150,
+            code: "CODE-2",
+          }),
+        ])
+      )
+    })
+
+    it("should add shipping method adjustments for shipping methods on multiple carts", async () => {
+      const [cartOne] = await service.create([
+        {
+          currency_code: "eur",
+        },
+      ])
+      const [cartTwo] = await service.create([
+        {
+          currency_code: "usd",
+        },
+      ])
+
+      const [shippingMethodOne] = await service.addShippingMethods(cartOne.id, [
+        {
+          amount: 100,
+          name: "test",
+        },
+      ])
+      const [shippingMethodTwo] = await service.addShippingMethods(cartTwo.id, [
+        {
+          amount: 200,
+          name: "test-2",
+        },
+      ])
+
+      await service.addShippingMethodAdjustments([
+        // item from cart one
+        {
+          shipping_method_id: shippingMethodOne.id,
+          amount: 100,
+          code: "FREE",
+        },
+        // item from cart two
+        {
+          shipping_method_id: shippingMethodTwo.id,
+          amount: 150,
+          code: "CODE-2",
+        },
+      ])
+
+      const cartOneMethods = await service.listShippingMethods(
+        { cart_id: cartOne.id },
+        { relations: ["adjustments"] }
+      )
+
+      const cartTwoMethods = await service.listShippingMethods(
+        { cart_id: cartTwo.id },
+        { relations: ["adjustments"] }
+      )
+
+      expect(cartOneMethods).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            adjustments: expect.arrayContaining([
+              expect.objectContaining({
+                shipping_method_id: shippingMethodOne.id,
+                amount: 100,
+                code: "FREE",
+              }),
+            ]),
+          }),
+        ])
+      )
+      expect(cartTwoMethods).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            adjustments: expect.arrayContaining([
+              expect.objectContaining({
+                shipping_method_id: shippingMethodTwo.id,
+                amount: 150,
+                code: "CODE-2",
+              }),
+            ]),
+          }),
+        ])
+      )
+    })
+
+    it("should throw if shipping method is not associated with cart", async () => {
+      const [cartOne] = await service.create([
+        {
+          currency_code: "eur",
+        },
+      ])
+
+      const [cartTwo] = await service.create([
+        {
+          currency_code: "eur",
+        },
+      ])
+
+      const [shippingMethodOne] = await service.addShippingMethods(cartOne.id, [
+        {
+          amount: 100,
+          name: "test",
+        },
+      ])
+
+      const error = await service
+        .addShippingMethodAdjustments(cartTwo.id, [
+          {
+            shipping_method_id: shippingMethodOne.id,
+            amount: 100,
+            code: "FREE",
+          },
+        ])
+        .catch((e) => e)
+
+      expect(error.message).toBe(
+        `Shipping method with id ${shippingMethodOne.id} does not exist on cart with id ${cartTwo.id}`
+      )
+    })
+  })
+
+  describe("removeShippingMethodAdjustments", () => {
+    it("should remove a shipping method succesfully", async () => {
+      const [createdCart] = await service.create([
+        {
+          currency_code: "eur",
+        },
+      ])
+
+      const [method] = await service.addShippingMethods(createdCart.id, [
+        {
+          amount: 100,
+          name: "test",
+        },
+      ])
+
+      const [adjustment] = await service.addShippingMethodAdjustments(
+        createdCart.id,
+        [
+          {
+            shipping_method_id: method.id,
+            amount: 50,
+            code: "50%",
+          },
+        ]
+      )
+
+      expect(adjustment.shipping_method_id).toBe(method.id)
+
+      await service.removeShippingMethodAdjustments(adjustment.id)
+
+      const adjustments = await service.listShippingMethodAdjustments({
+        shipping_method_id: method.id,
+      })
+
+      expect(adjustments?.length).toBe(0)
+    })
+
+    it("should remove a shipping method succesfully with selector", async () => {
+      const [createdCart] = await service.create([
+        {
+          currency_code: "eur",
+        },
+      ])
+
+      const [shippingMethod] = await service.addShippingMethods(
+        createdCart.id,
+        [
+          {
+            amount: 100,
+            name: "test",
+          },
+        ]
+      )
+
+      const [adjustment] = await service.addShippingMethodAdjustments(
+        createdCart.id,
+        [
+          {
+            shipping_method_id: shippingMethod.id,
+            amount: 50,
+            code: "50%",
+          },
+        ]
+      )
+
+      expect(adjustment.shipping_method_id).toBe(shippingMethod.id)
+
+      await service.removeShippingMethodAdjustments({
+        shipping_method_id: shippingMethod.id,
+      })
+
+      const adjustments = await service.listShippingMethodAdjustments({
+        shipping_method_id: shippingMethod.id,
+      })
+
+      expect(adjustments?.length).toBe(0)
+    })
+  })
 })
diff --git a/packages/cart/src/models/index.ts b/packages/cart/src/models/index.ts
index 33f78f0616d42..7f5c45b194832 100644
--- a/packages/cart/src/models/index.ts
+++ b/packages/cart/src/models/index.ts
@@ -4,6 +4,6 @@ export { default as LineItem } from "./line-item"
 export { default as LineItemAdjustment } from "./line-item-adjustment"
 export { default as LineItemTaxLine } from "./line-item-tax-line"
 export { default as ShippingMethod } from "./shipping-method"
-export { default as ShippingMethodAdjustmentLine } from "./shipping-method-adjustment-line"
+export { default as ShippingMethodAdjustment } from "./shipping-method-adjustment"
 export { default as ShippingMethodTaxLine } from "./shipping-method-tax-line"
 
diff --git a/packages/cart/src/models/line-item-adjustment.ts b/packages/cart/src/models/line-item-adjustment.ts
index 7e355ca463e04..341b22b793de4 100644
--- a/packages/cart/src/models/line-item-adjustment.ts
+++ b/packages/cart/src/models/line-item-adjustment.ts
@@ -10,7 +10,7 @@ import {
 import AdjustmentLine from "./adjustment-line"
 import LineItem from "./line-item"
 
-@Entity({ tableName: "cart_line_item_adjustment_line" })
+@Entity({ tableName: "cart_line_item_adjustment" })
 @Check<LineItemAdjustment>({
   expression: (columns) => `${columns.amount} >= 0`,
 })
@@ -18,7 +18,7 @@ export default class LineItemAdjustment extends AdjustmentLine {
   @ManyToOne(() => LineItem, {
     onDelete: "cascade",
     nullable: true,
-    index: "IDX_adjustment_line_item_id",
+    index: "IDX_adjustment_item_id",
   })
   item?: LineItem | null
 
diff --git a/packages/cart/src/models/shipping-method-adjustment-line.ts b/packages/cart/src/models/shipping-method-adjustment-line.ts
deleted file mode 100644
index e56e82313ab1d..0000000000000
--- a/packages/cart/src/models/shipping-method-adjustment-line.ts
+++ /dev/null
@@ -1,23 +0,0 @@
-import { generateEntityId } from "@medusajs/utils"
-import { BeforeCreate, Entity, ManyToOne, OnInit } from "@mikro-orm/core"
-import AdjustmentLine from "./adjustment-line"
-import ShippingMethod from "./shipping-method"
-
-@Entity({ tableName: "cart_shipping_method_adjustment_line" })
-export default class ShippingMethodAdjustmentLine extends AdjustmentLine {
-  @ManyToOne(() => ShippingMethod, {
-    joinColumn: "shipping_method",
-    fieldName: "shipping_method_id",
-  })
-  shipping_method: ShippingMethod
-
-  @BeforeCreate()
-  onCreate() {
-    this.id = generateEntityId(this.id, "casmadj")
-  }
-
-  @OnInit()
-  onInit() {
-    this.id = generateEntityId(this.id, "casmadj")
-  }
-}
diff --git a/packages/cart/src/models/shipping-method-adjustment.ts b/packages/cart/src/models/shipping-method-adjustment.ts
new file mode 100644
index 0000000000000..63b647379165d
--- /dev/null
+++ b/packages/cart/src/models/shipping-method-adjustment.ts
@@ -0,0 +1,33 @@
+import { generateEntityId } from "@medusajs/utils"
+import {
+  BeforeCreate,
+  Entity,
+  ManyToOne,
+  OnInit,
+  Property,
+} from "@mikro-orm/core"
+import AdjustmentLine from "./adjustment-line"
+import ShippingMethod from "./shipping-method"
+
+@Entity({ tableName: "cart_shipping_method_adjustment" })
+export default class ShippingMethodAdjustment extends AdjustmentLine {
+  @ManyToOne(() => ShippingMethod, {
+    onDelete: "cascade",
+    nullable: true,
+    index: "IDX_adjustment_shipping_method_id",
+  })
+  shipping_method: ShippingMethod | null
+
+  @Property({ columnType: "text" })
+  shipping_method_id: string
+
+  @BeforeCreate()
+  onCreate() {
+    this.id = generateEntityId(this.id, "casmadj")
+  }
+
+  @OnInit()
+  onInit() {
+    this.id = generateEntityId(this.id, "casmadj")
+  }
+}
diff --git a/packages/cart/src/models/shipping-method.ts b/packages/cart/src/models/shipping-method.ts
index 9d8eab459c31e..a46bbcc6b635f 100644
--- a/packages/cart/src/models/shipping-method.ts
+++ b/packages/cart/src/models/shipping-method.ts
@@ -12,7 +12,7 @@ import {
   Property,
 } from "@mikro-orm/core"
 import Cart from "./cart"
-import ShippingMethodAdjustmentLine from "./shipping-method-adjustment-line"
+import ShippingMethodAdjustment from "./shipping-method-adjustment"
 import ShippingMethodTaxLine from "./shipping-method-tax-line"
 
 @Entity({ tableName: "cart_shipping_method" })
@@ -62,13 +62,13 @@ export default class ShippingMethod {
   tax_lines = new Collection<ShippingMethodTaxLine>(this)
 
   @OneToMany(
-    () => ShippingMethodAdjustmentLine,
+    () => ShippingMethodAdjustment,
     (adjustment) => adjustment.shipping_method,
     {
       cascade: [Cascade.REMOVE],
     }
   )
-  adjustments = new Collection<ShippingMethodAdjustmentLine>(this)
+  adjustments = new Collection<ShippingMethodAdjustment>(this)
 
   /** COMPUTED PROPERTIES - START */
 
diff --git a/packages/cart/src/services/cart-module.ts b/packages/cart/src/services/cart-module.ts
index f9d479284cf1f..255253c3ba0e7 100644
--- a/packages/cart/src/services/cart-module.ts
+++ b/packages/cart/src/services/cart-module.ts
@@ -15,7 +15,13 @@ import {
   isObject,
   isString,
 } from "@medusajs/utils"
-import { Cart, LineItem, LineItemAdjustment, ShippingMethod } from "@models"
+import {
+  Cart,
+  LineItem,
+  LineItemAdjustment,
+  ShippingMethod,
+  ShippingMethodAdjustment,
+} from "@models"
 import { CreateLineItemDTO, UpdateLineItemDTO } from "@types"
 import { joinerConfig } from "../joiner-config"
 import * as services from "../services"
@@ -25,6 +31,7 @@ type InjectedDependencies = {
   cartService: services.CartService
   addressService: services.AddressService
   lineItemService: services.LineItemService
+  shippingMethodAdjustmentService: services.ShippingMethodAdjustmentService
   shippingMethodService: services.ShippingMethodService
   lineItemAdjustmentService: services.LineItemAdjustmentService
 }
@@ -34,6 +41,7 @@ export default class CartModuleService implements ICartModuleService {
   protected cartService_: services.CartService
   protected addressService_: services.AddressService
   protected lineItemService_: services.LineItemService
+  protected shippingMethodAdjustmentService_: services.ShippingMethodAdjustmentService
   protected shippingMethodService_: services.ShippingMethodService
   protected lineItemAdjustmentService_: services.LineItemAdjustmentService
 
@@ -43,6 +51,7 @@ export default class CartModuleService implements ICartModuleService {
       cartService,
       addressService,
       lineItemService,
+      shippingMethodAdjustmentService,
       shippingMethodService,
       lineItemAdjustmentService,
     }: InjectedDependencies,
@@ -52,6 +61,7 @@ export default class CartModuleService implements ICartModuleService {
     this.cartService_ = cartService
     this.addressService_ = addressService
     this.lineItemService_ = lineItemService
+    this.shippingMethodAdjustmentService_ = shippingMethodAdjustmentService
     this.shippingMethodService_ = shippingMethodService
     this.lineItemAdjustmentService_ = lineItemAdjustmentService
   }
@@ -584,7 +594,7 @@ export default class CartModuleService implements ICartModuleService {
   ): Promise<CartTypes.CartShippingMethodDTO[]>
   async addShippingMethods(
     cartId: string,
-    methods: CartTypes.CreateShippingMethodDTO[],
+    methods: CartTypes.CreateShippingMethodForSingleCartDTO[],
     sharedContext?: Context
   ): Promise<CartTypes.CartShippingMethodDTO[]>
 
@@ -618,9 +628,7 @@ export default class CartModuleService implements ICartModuleService {
 
     return await this.baseRepository_.serialize<
       CartTypes.CartShippingMethodDTO[]
-    >(methods, {
-      populate: true,
-    })
+    >(methods, { populate: true })
   }
 
   @InjectTransactionManager("baseRepository_")
@@ -882,4 +890,214 @@ export default class CartModuleService implements ICartModuleService {
 
     await this.lineItemAdjustmentService_.delete(ids, sharedContext)
   }
+
+  @InjectManager("baseRepository_")
+  async listShippingMethodAdjustments(
+    filters: CartTypes.FilterableShippingMethodAdjustmentProps = {},
+    config: FindConfig<CartTypes.ShippingMethodAdjustmentDTO> = {},
+    @MedusaContext() sharedContext: Context = {}
+  ) {
+    const adjustments = await this.shippingMethodAdjustmentService_.list(
+      filters,
+      config,
+      sharedContext
+    )
+
+    return await this.baseRepository_.serialize<
+      CartTypes.ShippingMethodAdjustmentDTO[]
+    >(adjustments, {
+      populate: true,
+    })
+  }
+
+  @InjectTransactionManager("baseRepository_")
+  async setShippingMethodAdjustments(
+    cartId: string,
+    adjustments: (
+      | CartTypes.CreateShippingMethodAdjustmentDTO
+      | CartTypes.UpdateShippingMethodAdjustmentDTO
+    )[],
+    @MedusaContext() sharedContext: Context = {}
+  ): Promise<CartTypes.ShippingMethodAdjustmentDTO[]> {
+    const cart = await this.retrieve(
+      cartId,
+      { select: ["id"], relations: ["shipping_methods.adjustments"] },
+      sharedContext
+    )
+
+    const methodIds = cart.shipping_methods?.map((method) => method.id)
+
+    const existingAdjustments = await this.listShippingMethodAdjustments(
+      { shipping_method_id: methodIds ?? [] },
+      { select: ["id"] },
+      sharedContext
+    )
+
+    let toUpdate: CartTypes.UpdateShippingMethodAdjustmentDTO[] = []
+    let toCreate: CartTypes.CreateShippingMethodAdjustmentDTO[] = []
+    for (const adj of adjustments) {
+      if ("id" in adj) {
+        toUpdate.push(adj as CartTypes.UpdateShippingMethodAdjustmentDTO)
+      } else {
+        toCreate.push(adj as CartTypes.CreateShippingMethodAdjustmentDTO)
+      }
+    }
+
+    const adjustmentsSet = new Set(toUpdate.map((a) => a.id))
+
+    const toDelete: CartTypes.ShippingMethodAdjustmentDTO[] = []
+
+    // From the existing adjustments, find the ones that are not passed in adjustments
+    existingAdjustments.forEach(
+      (adj: CartTypes.ShippingMethodAdjustmentDTO) => {
+        if (!adjustmentsSet.has(adj.id)) {
+          toDelete.push(adj)
+        }
+      }
+    )
+
+    if (toDelete.length) {
+      await this.shippingMethodAdjustmentService_.delete(
+        toDelete.map((adj) => adj!.id),
+        sharedContext
+      )
+    }
+
+    let result: ShippingMethodAdjustment[] = []
+
+    if (toCreate.length) {
+      const created = await this.shippingMethodAdjustmentService_.create(
+        toCreate,
+        sharedContext
+      )
+
+      result.push(...created)
+    }
+
+    if (toUpdate.length) {
+      const updated = await this.shippingMethodAdjustmentService_.update(
+        toUpdate,
+        sharedContext
+      )
+      result.push(...updated)
+    }
+
+    return await this.baseRepository_.serialize<
+      CartTypes.ShippingMethodAdjustmentDTO[]
+    >(result, {
+      populate: true,
+    })
+  }
+
+  async addShippingMethodAdjustments(
+    adjustments: CartTypes.CreateShippingMethodAdjustmentDTO[]
+  ): Promise<CartTypes.ShippingMethodAdjustmentDTO[]>
+  async addShippingMethodAdjustments(
+    adjustment: CartTypes.CreateShippingMethodAdjustmentDTO
+  ): Promise<CartTypes.ShippingMethodAdjustmentDTO>
+  async addShippingMethodAdjustments(
+    cartId: string,
+    adjustments: CartTypes.CreateShippingMethodAdjustmentDTO[],
+    sharedContext?: Context
+  ): Promise<CartTypes.ShippingMethodAdjustmentDTO[]>
+
+  @InjectTransactionManager("baseRepository_")
+  async addShippingMethodAdjustments(
+    cartIdOrData:
+      | string
+      | CartTypes.CreateShippingMethodAdjustmentDTO[]
+      | CartTypes.CreateShippingMethodAdjustmentDTO,
+    adjustments?: CartTypes.CreateShippingMethodAdjustmentDTO[],
+    @MedusaContext() sharedContext: Context = {}
+  ): Promise<
+    | CartTypes.ShippingMethodAdjustmentDTO[]
+    | CartTypes.ShippingMethodAdjustmentDTO
+  > {
+    let addedAdjustments: ShippingMethodAdjustment[] = []
+    if (isString(cartIdOrData)) {
+      const cart = await this.retrieve(
+        cartIdOrData,
+        { select: ["id"], relations: ["shipping_methods"] },
+        sharedContext
+      )
+
+      const methodIds = cart.shipping_methods?.map((method) => method.id)
+
+      for (const adj of adjustments || []) {
+        if (!methodIds?.includes(adj.shipping_method_id)) {
+          throw new MedusaError(
+            MedusaError.Types.INVALID_DATA,
+            `Shipping method with id ${adj.shipping_method_id} does not exist on cart with id ${cartIdOrData}`
+          )
+        }
+      }
+
+      addedAdjustments = await this.shippingMethodAdjustmentService_.create(
+        adjustments as CartTypes.CreateShippingMethodAdjustmentDTO[],
+        sharedContext
+      )
+    } else {
+      const data = Array.isArray(cartIdOrData) ? cartIdOrData : [cartIdOrData]
+
+      addedAdjustments = await this.shippingMethodAdjustmentService_.create(
+        data as CartTypes.CreateShippingMethodAdjustmentDTO[],
+        sharedContext
+      )
+    }
+
+    if (isObject(cartIdOrData)) {
+      return await this.baseRepository_.serialize<CartTypes.ShippingMethodAdjustmentDTO>(
+        addedAdjustments[0],
+        {
+          populate: true,
+        }
+      )
+    }
+
+    return await this.baseRepository_.serialize<
+      CartTypes.ShippingMethodAdjustmentDTO[]
+    >(addedAdjustments, {
+      populate: true,
+    })
+  }
+
+  async removeShippingMethodAdjustments(
+    adjustmentIds: string[],
+    sharedContext?: Context
+  ): Promise<void>
+  async removeShippingMethodAdjustments(
+    adjustmentId: string,
+    sharedContext?: Context
+  ): Promise<void>
+  async removeShippingMethodAdjustments(
+    selector: Partial<CartTypes.ShippingMethodAdjustmentDTO>,
+    sharedContext?: Context
+  ): Promise<void>
+
+  async removeShippingMethodAdjustments(
+    adjustmentIdsOrSelector:
+      | string
+      | string[]
+      | Partial<CartTypes.ShippingMethodAdjustmentDTO>,
+    @MedusaContext() sharedContext: Context = {}
+  ): Promise<void> {
+    let ids: string[] = []
+    if (isObject(adjustmentIdsOrSelector)) {
+      const adjustments = await this.listShippingMethodAdjustments(
+        {
+          ...adjustmentIdsOrSelector,
+        } as Partial<CartTypes.ShippingMethodAdjustmentDTO>,
+        { select: ["id"] },
+        sharedContext
+      )
+
+      ids = adjustments.map((adj) => adj.id)
+    } else {
+      ids = Array.isArray(adjustmentIdsOrSelector)
+        ? adjustmentIdsOrSelector
+        : [adjustmentIdsOrSelector]
+    }
+
+    await this.shippingMethodAdjustmentService_.delete(ids, sharedContext)
+  }
 }
diff --git a/packages/cart/src/services/index.ts b/packages/cart/src/services/index.ts
index c982c3e826ca3..cd2616864ad55 100644
--- a/packages/cart/src/services/index.ts
+++ b/packages/cart/src/services/index.ts
@@ -4,4 +4,5 @@ export { default as CartModuleService } from "./cart-module"
 export { default as LineItemService } from "./line-item"
 export { default as LineItemAdjustmentService } from "./line-item-adjustment"
 export { default as ShippingMethodService } from "./shipping-method"
+export { default as ShippingMethodAdjustmentService } from "./shipping-method-adjustment"
 
diff --git a/packages/cart/src/services/shipping-method-adjustment.ts b/packages/cart/src/services/shipping-method-adjustment.ts
new file mode 100644
index 0000000000000..5688cd662babe
--- /dev/null
+++ b/packages/cart/src/services/shipping-method-adjustment.ts
@@ -0,0 +1,26 @@
+import { DAL } from "@medusajs/types"
+import { ModulesSdkUtils } from "@medusajs/utils"
+import { ShippingMethodAdjustment } from "@models"
+import {
+  CreateShippingMethodAdjustmentDTO,
+  UpdateShippingMethodAdjustmentDTO,
+} from "@types"
+
+type InjectedDependencies = {
+  shippingMethodAdjustmentRepository: DAL.RepositoryService
+}
+
+export default class ShippingMethodAdjustmentService<
+  TEntity extends ShippingMethodAdjustment = ShippingMethodAdjustment
+> extends ModulesSdkUtils.abstractServiceFactory<
+  InjectedDependencies,
+  {
+    create: CreateShippingMethodAdjustmentDTO
+    update: UpdateShippingMethodAdjustmentDTO
+  }
+>(ShippingMethodAdjustment)<TEntity> {
+  constructor(container: InjectedDependencies) {
+    // @ts-ignore
+    super(...arguments)
+  }
+}
diff --git a/packages/cart/src/types/index.ts b/packages/cart/src/types/index.ts
index d5866dad06a01..98891da01912b 100644
--- a/packages/cart/src/types/index.ts
+++ b/packages/cart/src/types/index.ts
@@ -4,8 +4,9 @@ export * from "./address"
 export * from "./cart"
 export * from "./line-item"
 export * from "./line-item-adjustment"
-export * from "./shipping-method"
 export * from "./repositories"
+export * from "./shipping-method"
+export * from "./shipping-method-adjustment"
 
 export type InitializeModuleInjectableDependencies = {
   logger?: Logger
diff --git a/packages/cart/src/types/repositories.ts b/packages/cart/src/types/repositories.ts
index 2b38ef909cdbf..60d732c873b37 100644
--- a/packages/cart/src/types/repositories.ts
+++ b/packages/cart/src/types/repositories.ts
@@ -1,5 +1,11 @@
 import { DAL } from "@medusajs/types"
-import { Cart, LineItem, LineItemAdjustment, ShippingMethod } from "@models"
+import {
+  Cart,
+  LineItem,
+  LineItemAdjustment,
+  ShippingMethod,
+  ShippingMethodAdjustment,
+} from "@models"
 import { CreateAddressDTO, UpdateAddressDTO } from "./address"
 import { CreateCartDTO, UpdateCartDTO } from "./cart"
 import { CreateLineItemDTO, UpdateLineItemDTO } from "./line-item"
@@ -11,6 +17,10 @@ import {
   CreateShippingMethodDTO,
   UpdateShippingMethodDTO,
 } from "./shipping-method"
+import {
+  CreateShippingMethodAdjustmentDTO,
+  UpdateShippingMethodAdjustmentDTO,
+} from "./shipping-method-adjustment"
 
 // eslint-disable-next-line @typescript-eslint/no-empty-interface
 export interface IAddressRepository<TEntity extends Cart = Cart>
@@ -62,3 +72,13 @@ export interface ILineItemAdjustmentRepository<
       update: UpdateLineItemAdjustmentDTO
     }
   > {}
+
+export interface IShippingMethodAdjustmentRepository<
+  TEntity extends ShippingMethodAdjustment = ShippingMethodAdjustment
+> extends DAL.RepositoryService<
+    TEntity,
+    {
+      create: CreateShippingMethodAdjustmentDTO
+      update: UpdateShippingMethodAdjustmentDTO
+    }
+  > {}
diff --git a/packages/cart/src/types/shipping-method-adjustment.ts b/packages/cart/src/types/shipping-method-adjustment.ts
new file mode 100644
index 0000000000000..e6e5c945dba26
--- /dev/null
+++ b/packages/cart/src/types/shipping-method-adjustment.ts
@@ -0,0 +1,17 @@
+export interface CreateShippingMethodAdjustmentDTO {
+  shipping_method_id: string
+  code: string
+  amount: number
+  description?: string
+  promotion_id?: string
+  provider_id?: string
+}
+
+export interface UpdateShippingMethodAdjustmentDTO {
+  id: string
+  code?: string
+  amount?: number
+  description?: string
+  promotion_id?: string
+  provider_id?: string
+}
diff --git a/packages/types/src/cart/common.ts b/packages/types/src/cart/common.ts
index 08d9a567700c2..b163809a9a5f9 100644
--- a/packages/types/src/cart/common.ts
+++ b/packages/types/src/cart/common.ts
@@ -40,11 +40,15 @@ export interface AdjustmentLineDTO {
   updated_at: Date | string
 }
 
-export interface ShippingMethodAdjustmentLineDTO extends AdjustmentLineDTO {
+export interface ShippingMethodAdjustmentDTO extends AdjustmentLineDTO {
   /**
    * The associated shipping method
    */
   shipping_method: CartShippingMethodDTO
+  /**
+   * The ID of the associated shipping method
+   */
+  shipping_method_id: string
 }
 
 export interface LineItemAdjustmentDTO extends AdjustmentLineDTO {
@@ -227,7 +231,7 @@ export interface CartShippingMethodDTO {
    *
    * @expandable
    */
-  adjustments?: ShippingMethodAdjustmentLineDTO[]
+  adjustments?: ShippingMethodAdjustmentDTO[]
 
   /**
    * When the shipping method was created.
@@ -518,6 +522,14 @@ export interface FilterableShippingMethodProps
   shipping_option_id?: string | string[]
 }
 
+export interface FilterableShippingMethodAdjustmentProps
+  extends BaseFilterable<FilterableShippingMethodAdjustmentProps> {
+  id?: string | string[]
+  shipping_method_id?: string | string[]
+  promotion_id?: string | string[]
+  provider_id?: string | string[]
+}
+
 /**
  * TODO: Remove this in favor of CartDTO, when module is released
  * @deprecated Use CartDTO instead
diff --git a/packages/types/src/cart/mutations.ts b/packages/types/src/cart/mutations.ts
index 98da700bbbe27..ef9247c34957e 100644
--- a/packages/types/src/cart/mutations.ts
+++ b/packages/types/src/cart/mutations.ts
@@ -208,4 +208,22 @@ export interface UpdateShippingMethodDTO {
   adjustments?: CreateAdjustmentDTO[] | UpdateAdjustmentDTO[]
 }
 
+export interface CreateShippingMethodAdjustmentDTO {
+  shipping_method_id: string
+  code: string
+  amount: number
+  description?: string
+  promotion_id?: string
+  provider_id?: string
+}
+
+export interface UpdateShippingMethodAdjustmentDTO {
+  id: string
+  code?: string
+  amount?: number
+  description?: string
+  promotion_id?: string
+  provider_id?: string
+}
+
 /** SHIPPING METHODS END */
diff --git a/packages/types/src/cart/service.ts b/packages/types/src/cart/service.ts
index 1af01d344d5d7..58f7adcd22474 100644
--- a/packages/types/src/cart/service.ts
+++ b/packages/types/src/cart/service.ts
@@ -2,29 +2,34 @@ import { FindConfig } from "../common"
 import { IModuleService } from "../modules-sdk"
 import { Context } from "../shared-context"
 import {
-    CartAddressDTO,
-    CartDTO,
-    CartLineItemDTO,
-    CartShippingMethodDTO,
-    FilterableAddressProps,
-    FilterableCartProps,
-    FilterableLineItemAdjustmentProps,
-    FilterableLineItemProps,
-    FilterableShippingMethodProps,
-    LineItemAdjustmentDTO,
+  CartAddressDTO,
+  CartDTO,
+  CartLineItemDTO,
+  CartShippingMethodDTO,
+  FilterableAddressProps,
+  FilterableCartProps,
+  FilterableLineItemAdjustmentProps,
+  FilterableLineItemProps,
+  FilterableShippingMethodAdjustmentProps,
+  FilterableShippingMethodProps,
+  LineItemAdjustmentDTO,
+  ShippingMethodAdjustmentDTO,
 } from "./common"
 import {
-    CreateAddressDTO,
-    CreateAdjustmentDTO,
-    CreateCartDTO,
-    CreateLineItemDTO,
-    CreateLineItemForCartDTO,
-    CreateShippingMethodDTO,
-    UpdateAddressDTO,
-    UpdateCartDTO,
-    UpdateLineItemDTO,
-    UpdateLineItemWithSelectorDTO,
-    UpsertLineItemAdjustmentDTO
+  CreateAddressDTO,
+  CreateAdjustmentDTO,
+  CreateCartDTO,
+  CreateLineItemDTO,
+  CreateLineItemForCartDTO,
+  CreateShippingMethodAdjustmentDTO,
+  CreateShippingMethodDTO,
+  CreateShippingMethodForSingleCartDTO,
+  UpdateAddressDTO,
+  UpdateCartDTO,
+  UpdateLineItemDTO,
+  UpdateLineItemWithSelectorDTO,
+  UpdateShippingMethodAdjustmentDTO,
+  UpsertLineItemAdjustmentDTO,
 } from "./mutations"
 
 export interface ICartModuleService extends IModuleService {
@@ -126,7 +131,7 @@ export interface ICartModuleService extends IModuleService {
   listShippingMethods(
     filters: FilterableShippingMethodProps,
     config: FindConfig<CartShippingMethodDTO>,
-    sharedContext: Context
+    sharedContext?: Context
   ): Promise<CartShippingMethodDTO[]>
 
   addShippingMethods(
@@ -137,7 +142,7 @@ export interface ICartModuleService extends IModuleService {
   ): Promise<CartShippingMethodDTO[]>
   addShippingMethods(
     cartId: string,
-    methods: CreateShippingMethodDTO[],
+    methods: CreateShippingMethodForSingleCartDTO[],
     sharedContext?: Context
   ): Promise<CartShippingMethodDTO[]>
 
@@ -189,4 +194,44 @@ export interface ICartModuleService extends IModuleService {
     selector: Partial<LineItemAdjustmentDTO>,
     sharedContext?: Context
   ): Promise<void>
+
+  listShippingMethodAdjustments(
+    filters: FilterableShippingMethodAdjustmentProps,
+    config?: FindConfig<ShippingMethodAdjustmentDTO>,
+    sharedContext?: Context
+  ): Promise<ShippingMethodAdjustmentDTO[]>
+
+  addShippingMethodAdjustments(
+    data: CreateShippingMethodAdjustmentDTO[]
+  ): Promise<ShippingMethodAdjustmentDTO[]>
+  addShippingMethodAdjustments(
+    data: CreateShippingMethodAdjustmentDTO
+  ): Promise<ShippingMethodAdjustmentDTO>
+  addShippingMethodAdjustments(
+    cartId: string,
+    data: CreateShippingMethodAdjustmentDTO[],
+    sharedContext?: Context
+  ): Promise<ShippingMethodAdjustmentDTO[]>
+
+  setShippingMethodAdjustments(
+    cartId: string,
+    data: (
+      | CreateShippingMethodAdjustmentDTO
+      | UpdateShippingMethodAdjustmentDTO
+    )[],
+    sharedContext?: Context
+  ): Promise<ShippingMethodAdjustmentDTO[]>
+
+  removeShippingMethodAdjustments(
+    adjustmentIds: string[],
+    sharedContext?: Context
+  ): Promise<void>
+  removeShippingMethodAdjustments(
+    adjustmentId: string,
+    sharedContext?: Context
+  ): Promise<void>
+  removeShippingMethodAdjustments(
+    selector: Partial<ShippingMethodAdjustmentDTO>,
+    sharedContext?: Context
+  ): Promise<void>
 }