diff --git a/.changeset/cool-shrimps-juggle.md b/.changeset/cool-shrimps-juggle.md
new file mode 100644
index 000000000..7bdc36c67
--- /dev/null
+++ b/.changeset/cool-shrimps-juggle.md
@@ -0,0 +1,5 @@
+---
+'@hey-api/openapi-ts': patch
+---
+
+fix: handle nullable enums in experimental parser
diff --git a/packages/openapi-ts/src/openApi/3.0.x/parser/schema.ts b/packages/openapi-ts/src/openApi/3.0.x/parser/schema.ts
index 976684220..5049d4811 100644
--- a/packages/openapi-ts/src/openApi/3.0.x/parser/schema.ts
+++ b/packages/openapi-ts/src/openApi/3.0.x/parser/schema.ts
@@ -407,23 +407,19 @@ const parseEnum = ({
 
   for (const [index, enumValue] of schema.enum.entries()) {
     const typeOfEnumValue = typeof enumValue;
+    let enumType: SchemaType | 'null' | undefined;
+
     if (
       typeOfEnumValue === 'string' ||
       typeOfEnumValue === 'number' ||
       typeOfEnumValue === 'boolean'
     ) {
-      const enumSchema = parseOneType({
-        context,
-        schema: {
-          description: schema['x-enum-descriptions']?.[index],
-          title:
-            schema['x-enum-varnames']?.[index] ??
-            schema['x-enumNames']?.[index],
-          type: typeOfEnumValue,
-        },
-      });
-      enumSchema.const = enumValue;
-      schemaItems.push(enumSchema);
+      enumType = typeOfEnumValue;
+    } else if (enumValue === null) {
+      // nullable must be true
+      if (schema.nullable) {
+        enumType = 'null';
+      }
     } else {
       console.warn(
         '🚨',
@@ -431,12 +427,30 @@ const parseEnum = ({
         schema.enum,
       );
     }
-  }
 
-  if (schema.nullable) {
-    schemaItems.push({
-      type: 'null',
+    if (!enumType) {
+      continue;
+    }
+
+    const enumSchema = parseOneType({
+      context,
+      schema: {
+        description: schema['x-enum-descriptions']?.[index],
+        title:
+          schema['x-enum-varnames']?.[index] ?? schema['x-enumNames']?.[index],
+        // cast enum to string temporarily
+        type: enumType === 'null' ? 'string' : enumType,
+      },
     });
+
+    enumSchema.const = enumValue;
+
+    // cast enum back
+    if (enumType === 'null') {
+      enumSchema.type = enumType;
+    }
+
+    schemaItems.push(enumSchema);
   }
 
   irSchema = addItemsToSchema({
diff --git a/packages/openapi-ts/src/openApi/3.1.x/parser/schema.ts b/packages/openapi-ts/src/openApi/3.1.x/parser/schema.ts
index d44311f7d..cdc124915 100644
--- a/packages/openapi-ts/src/openApi/3.1.x/parser/schema.ts
+++ b/packages/openapi-ts/src/openApi/3.1.x/parser/schema.ts
@@ -443,27 +443,23 @@ const parseEnum = ({
   irSchema.type = 'enum';
 
   const schemaItems: Array<IRSchemaObject> = [];
+  const schemaTypes = getSchemaTypes({ schema });
 
   for (const [index, enumValue] of schema.enum.entries()) {
     const typeOfEnumValue = typeof enumValue;
+    let enumType: SchemaType | undefined;
+
     if (
       typeOfEnumValue === 'string' ||
       typeOfEnumValue === 'number' ||
       typeOfEnumValue === 'boolean'
     ) {
-      schemaItems.push(
-        parseOneType({
-          context,
-          schema: {
-            const: enumValue,
-            description: schema['x-enum-descriptions']?.[index],
-            title:
-              schema['x-enum-varnames']?.[index] ??
-              schema['x-enumNames']?.[index],
-            type: typeOfEnumValue,
-          },
-        }),
-      );
+      enumType = typeOfEnumValue;
+    } else if (enumValue === null) {
+      // type must contain null
+      if (schemaTypes.includes('null')) {
+        enumType = 'null';
+      }
     } else {
       console.warn(
         '🚨',
@@ -471,6 +467,24 @@ const parseEnum = ({
         schema.enum,
       );
     }
+
+    if (!enumType) {
+      continue;
+    }
+
+    schemaItems.push(
+      parseOneType({
+        context,
+        schema: {
+          const: enumValue,
+          description: schema['x-enum-descriptions']?.[index],
+          title:
+            schema['x-enum-varnames']?.[index] ??
+            schema['x-enumNames']?.[index],
+          type: enumType,
+        },
+      }),
+    );
   }
 
   irSchema = addItemsToSchema({
diff --git a/packages/openapi-ts/src/openApi/index.ts b/packages/openapi-ts/src/openApi/index.ts
index f50418b10..fe8b41ea7 100644
--- a/packages/openapi-ts/src/openApi/index.ts
+++ b/packages/openapi-ts/src/openApi/index.ts
@@ -75,31 +75,26 @@ export const parseExperimental = ({
     spec: spec as Record<string, any>,
   });
 
+  // TODO: parser - handle Swagger 2.0
+
   const ctx = context as IRContext<OpenApiV3_0_X | OpenApiV3_1_X>;
   switch (ctx.spec.openapi) {
-    // TODO: parser - handle Swagger 2.0
     case '3.0.0':
     case '3.0.1':
     case '3.0.2':
     case '3.0.3':
     case '3.0.4':
       parseV3_0_X(context as IRContext<OpenApiV3_0_X>);
-      break;
+      return context;
     case '3.1.0':
     case '3.1.1':
       parseV3_1_X(context as IRContext<OpenApiV3_1_X>);
-      break;
+      return context;
     default:
       // TODO: parser - uncomment after removing legacy parser.
       // For now, we fall back to legacy parser if spec version
       // is not supported
       // throw new Error('Unsupported OpenAPI specification');
-      break;
-  }
-
-  if (!Object.keys(context.ir).length) {
-    return;
+      return;
   }
-
-  return context;
 };
diff --git a/packages/openapi-ts/test/3.0.x.spec.ts b/packages/openapi-ts/test/3.0.x.spec.ts
index d3517284e..f55092f2f 100644
--- a/packages/openapi-ts/test/3.0.x.spec.ts
+++ b/packages/openapi-ts/test/3.0.x.spec.ts
@@ -55,6 +55,13 @@ describe(`OpenAPI ${VERSION}`, () => {
       }),
       description: 'escapes enum values',
     },
+    {
+      config: createConfig({
+        input: 'enum-null.json',
+        output: 'enum-null',
+      }),
+      description: 'handles null enums',
+    },
   ];
 
   it.each(scenarios)('$description', async ({ config }) => {
diff --git a/packages/openapi-ts/test/3.1.x.spec.ts b/packages/openapi-ts/test/3.1.x.spec.ts
index 037d7ee8a..012c285c0 100644
--- a/packages/openapi-ts/test/3.1.x.spec.ts
+++ b/packages/openapi-ts/test/3.1.x.spec.ts
@@ -62,6 +62,13 @@ describe(`OpenAPI ${VERSION}`, () => {
       }),
       description: 'escapes enum values',
     },
+    {
+      config: createConfig({
+        input: 'enum-null.json',
+        output: 'enum-null',
+      }),
+      description: 'handles null enums',
+    },
     {
       config: createConfig({
         input: 'object-properties-all-of.json',
diff --git a/packages/openapi-ts/test/__snapshots__/3.0.x/enum-null/index.ts b/packages/openapi-ts/test/__snapshots__/3.0.x/enum-null/index.ts
new file mode 100644
index 000000000..56bade120
--- /dev/null
+++ b/packages/openapi-ts/test/__snapshots__/3.0.x/enum-null/index.ts
@@ -0,0 +1,2 @@
+// This file is auto-generated by @hey-api/openapi-ts
+export * from './types.gen';
\ No newline at end of file
diff --git a/packages/openapi-ts/test/__snapshots__/3.0.x/enum-null/types.gen.ts b/packages/openapi-ts/test/__snapshots__/3.0.x/enum-null/types.gen.ts
new file mode 100644
index 000000000..1e159325e
--- /dev/null
+++ b/packages/openapi-ts/test/__snapshots__/3.0.x/enum-null/types.gen.ts
@@ -0,0 +1,7 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+export type Foo = 'foo' | 'bar' | null;
+
+export type Bar = 'foo' | 'bar';
+
+export type Baz = 'foo' | 'bar';
\ No newline at end of file
diff --git a/packages/openapi-ts/test/__snapshots__/3.1.x/enum-null/index.ts b/packages/openapi-ts/test/__snapshots__/3.1.x/enum-null/index.ts
new file mode 100644
index 000000000..56bade120
--- /dev/null
+++ b/packages/openapi-ts/test/__snapshots__/3.1.x/enum-null/index.ts
@@ -0,0 +1,2 @@
+// This file is auto-generated by @hey-api/openapi-ts
+export * from './types.gen';
\ No newline at end of file
diff --git a/packages/openapi-ts/test/__snapshots__/3.1.x/enum-null/types.gen.ts b/packages/openapi-ts/test/__snapshots__/3.1.x/enum-null/types.gen.ts
new file mode 100644
index 000000000..1e159325e
--- /dev/null
+++ b/packages/openapi-ts/test/__snapshots__/3.1.x/enum-null/types.gen.ts
@@ -0,0 +1,7 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+export type Foo = 'foo' | 'bar' | null;
+
+export type Bar = 'foo' | 'bar';
+
+export type Baz = 'foo' | 'bar';
\ No newline at end of file
diff --git a/packages/openapi-ts/test/sample.cjs b/packages/openapi-ts/test/sample.cjs
index 80fe4d0be..b5028a268 100644
--- a/packages/openapi-ts/test/sample.cjs
+++ b/packages/openapi-ts/test/sample.cjs
@@ -11,9 +11,9 @@ const main = async () => {
     // debug: true,
     experimentalParser: true,
     input: {
-      include:
-        '^(#/components/schemas/import|#/paths/api/v{api-version}/simple/options)$',
-      path: './test/spec/3.1.x/full.json',
+      // include:
+      //   '^(#/components/schemas/import|#/paths/api/v{api-version}/simple/options)$',
+      path: './test/spec/3.1.x/enum-null.json',
       // path: 'https://mongodb-mms-prod-build-server.s3.amazonaws.com/openapi/2caffd88277a4e27c95dcefc7e3b6a63a3b03297-v2-2023-11-15.json',
     },
     // name: 'foo',
@@ -27,12 +27,12 @@ const main = async () => {
       //   name: '@hey-api/schemas',
       //   type: 'json',
       // },
-      {
-        // asClass: true,
-        // include...
-        name: '@hey-api/services',
-        // serviceNameBuilder: '^Parameters',
-      },
+      // {
+      //   // asClass: true,
+      //   // include...
+      //   name: '@hey-api/services',
+      //   // serviceNameBuilder: '^Parameters',
+      // },
       // {
       //   dates: true,
       //   name: '@hey-api/transformers',
diff --git a/packages/openapi-ts/test/spec/3.0.x/enum-null.json b/packages/openapi-ts/test/spec/3.0.x/enum-null.json
new file mode 100644
index 000000000..445112288
--- /dev/null
+++ b/packages/openapi-ts/test/spec/3.0.x/enum-null.json
@@ -0,0 +1,25 @@
+{
+  "openapi": "3.0.2",
+  "info": {
+    "title": "OpenAPI 3.0.2 enum null example",
+    "version": "1"
+  },
+  "components": {
+    "schemas": {
+      "Foo": {
+        "enum": ["foo", "bar", null],
+        "nullable": true,
+        "type": "string"
+      },
+      "Bar": {
+        "enum": ["foo", "bar", null],
+        "type": "string"
+      },
+      "Baz": {
+        "enum": ["foo", "bar"],
+        "nullable": true,
+        "type": "string"
+      }
+    }
+  }
+}
diff --git a/packages/openapi-ts/test/spec/3.1.x/enum-null.json b/packages/openapi-ts/test/spec/3.1.x/enum-null.json
new file mode 100644
index 000000000..a75baeada
--- /dev/null
+++ b/packages/openapi-ts/test/spec/3.1.x/enum-null.json
@@ -0,0 +1,23 @@
+{
+  "openapi": "3.1.0",
+  "info": {
+    "title": "OpenAPI 3.1.0 enum null example",
+    "version": "1"
+  },
+  "components": {
+    "schemas": {
+      "Foo": {
+        "enum": ["foo", "bar", null],
+        "type": ["string", "null"]
+      },
+      "Bar": {
+        "enum": ["foo", "bar", null],
+        "type": "string"
+      },
+      "Baz": {
+        "enum": ["foo", "bar"],
+        "type": ["string", "null"]
+      }
+    }
+  }
+}