diff --git a/core/app/models/spree/tax_rate.rb b/core/app/models/spree/tax_rate.rb
index 627682f2d0f..e50b004872b 100644
--- a/core/app/models/spree/tax_rate.rb
+++ b/core/app/models/spree/tax_rate.rb
@@ -87,23 +87,6 @@ class TaxRate < Spree::Base
     end
     scope :included_in_price, -> { where(included_in_price: true) }
 
-    # Creates necessary tax adjustments for the order.
-    #
-    # @deprecated Please use `Spree::Tax::OrderAdjuster#adjust!` instead
-    def adjust(_order_tax_zone, item)
-      Spree::Deprecation.warn("`Spree::TaxRate#adjust` is deprecated. Please use `Spree::Tax::OrderAdjuster#adjust!` instead.", caller)
-
-      amount = compute_amount(item)
-
-      item.adjustments.create!(
-        source: self,
-        amount: amount,
-        order_id: item.order_id,
-        label: adjustment_label(amount),
-        included: included_in_price
-      )
-    end
-
     # This method is used by Adjustment#update to recalculate the cost.
     def compute_amount(item)
       calculator.compute(item)
diff --git a/core/spec/models/spree/tax_rate_spec.rb b/core/spec/models/spree/tax_rate_spec.rb
index 5411ecb6190..4fcd0ef5b11 100644
--- a/core/spec/models/spree/tax_rate_spec.rb
+++ b/core/spec/models/spree/tax_rate_spec.rb
@@ -187,98 +187,6 @@
     end
   end
 
-  describe "#adjust" do
-    let(:taxable_address) { create(:address) }
-    let(:order) { create(:order_with_line_items, ship_address: order_address) }
-    let(:tax_zone) { create(:zone, countries: [taxable_address.country]) }
-    let(:foreign_address) { create(:address, country_iso_code: "CA") }
-    let!(:foreign_zone) { create(:zone, countries: [foreign_address.country]) }
-    let(:tax_rate) do
-      create(:tax_rate,
-        included_in_price: included_in_price,
-        show_rate_in_label: show_rate_in_label,
-        amount: 0.125,
-        zone: tax_zone)
-    end
-
-    let(:item) { order.line_items.first }
-
-    before do
-      expect(Spree::Deprecation).to receive(:warn).
-        with(/^`Spree::TaxRate#adjust` is deprecated/, any_args)
-    end
-
-    describe 'adjustments' do
-      before do
-        tax_rate.adjust(nil, item)
-      end
-
-      let(:adjustment_label) { item.adjustments.tax.first.label }
-
-      context 'for included rates' do
-        let(:included_in_price) { true }
-        let(:order_address) { taxable_address }
-
-        context 'with show rate in label' do
-          let(:show_rate_in_label) { true }
-
-          it 'shows the rate in the label' do
-            expect(adjustment_label).to include("12.500%")
-          end
-
-          it 'adds a remark that the rate is included in the price' do
-            expect(adjustment_label).to include("Included in Price")
-          end
-        end
-
-        context 'with show rate in label turned off' do
-          let(:show_rate_in_label) { false }
-
-          it 'does not show the rate in the label' do
-            expect(adjustment_label).not_to include("12.500%")
-          end
-
-          it 'does not have two consecutive spaces' do
-            expect(adjustment_label).not_to include("  ")
-          end
-
-          it 'adds a remark that the rate is included in the price' do
-            expect(adjustment_label).to include("Included in Price")
-          end
-        end
-      end
-
-      context 'for additional rates' do
-        let(:included_in_price) { false }
-        let(:order_address) { taxable_address }
-
-        context 'with show rate in label' do
-          let(:show_rate_in_label) { true }
-
-          it 'shows the rate in the label' do
-            expect(adjustment_label).to include("12.500%")
-          end
-
-          it 'does not add a remark that the rate is included in the price' do
-            expect(adjustment_label).not_to include("Included in Price")
-          end
-        end
-
-        context 'with show rate in label turned off' do
-          let(:show_rate_in_label) { false }
-
-          it 'does not show the rate in the label' do
-            expect(adjustment_label).not_to include("12.500%")
-          end
-
-          it 'does not add a remark that the rate is included in the price' do
-            expect(adjustment_label).not_to include("Included in Price")
-          end
-        end
-      end
-    end
-  end
-
   describe "#active?" do
     subject(:rate) { create(:tax_rate, validity).active? }