diff --git a/src/SmartTransactionsController.test.ts b/src/SmartTransactionsController.test.ts
index 2d77a73..0f303bc 100644
--- a/src/SmartTransactionsController.test.ts
+++ b/src/SmartTransactionsController.test.ts
@@ -2194,6 +2194,48 @@ describe('SmartTransactionsController', () => {
         expect(apiCall.isDone()).toBe(true);
       });
     });
+
+    it('sends Authorization header when getBearerToken is provided', async () => {
+      const bearerToken = 'test-bearer-token-123';
+      await withController(
+        {
+          options: {
+            getBearerToken: async () => Promise.resolve(bearerToken),
+          },
+        },
+        async ({ controller }) => {
+          const apiCall = nock(API_BASE_URL)
+            .post(`/networks/${ethereumChainIdDec}/cancel`)
+            .matchHeader('Authorization', `Bearer ${bearerToken}`)
+            .reply(200, { message: 'successful' });
+
+          await controller.cancelSmartTransaction('uuid1');
+
+          expect(apiCall.isDone()).toBe(true);
+        },
+      );
+    });
+
+    it('sends Authorization header to Sentinel /network when getBearerToken is provided', async () => {
+      const bearerToken = 'test-bearer-token-456';
+      await withController(
+        {
+          options: {
+            getBearerToken: async () => Promise.resolve(bearerToken),
+          },
+        },
+        async ({ controller }) => {
+          const apiCall = nock(SENTINEL_API_BASE_URL_MAP[ethereumChainIdDec])
+            .get(`/network`)
+            .matchHeader('Authorization', `Bearer ${bearerToken}`)
+            .reply(200, createSuccessLivenessApiResponse());
+
+          await controller.fetchLiveness();
+
+          expect(apiCall.isDone()).toBe(true);
+        },
+      );
+    });
   });
 
   describe('getTransactions', () => {
diff --git a/src/SmartTransactionsController.ts b/src/SmartTransactionsController.ts
index ee5dc6f..d537a22 100644
--- a/src/SmartTransactionsController.ts
+++ b/src/SmartTransactionsController.ts
@@ -37,9 +37,11 @@ import { BigNumber } from 'bignumber.js';
 import cloneDeep from 'lodash/cloneDeep';
 
 import {
+  API_BASE_URL,
   DEFAULT_DISABLED_SMART_TRANSACTIONS_FEATURE_FLAGS,
   MetaMetricsEventCategory,
   MetaMetricsEventName,
+  SENTINEL_API_BASE_URL_MAP,
   SmartTransactionsTraceName,
 } from './constants';
 import {
@@ -230,6 +232,14 @@ type SmartTransactionsControllerOptions = {
    * removed in a future version.
    */
   getFeatureFlags?: () => FeatureFlags;
+  /**
+   * Optional callback to obtain a bearer token for authenticating requests to
+   * the Transaction API. When provided, the token is sent in the
+   * Authorization header for all Transaction API calls. Can be used with
+   * the authentication flow from @metamask/core-backend (e.g. from
+   * AuthenticationController.getBearerToken).
+   */
+  getBearerToken?: () => Promise<string | undefined> | string | undefined;
   trace?: TraceCallback;
 };
 
@@ -258,6 +268,11 @@ export class SmartTransactionsController extends StaticIntervalPollingController
 
   readonly #getMetaMetricsProps: () => Promise<MetaMetricsProps>;
 
+  readonly #getBearerToken?: () =>
+    | Promise<string | undefined>
+    | string
+    | undefined;
+
   #trace: TraceCallback;
 
   /**
@@ -292,11 +307,28 @@ export class SmartTransactionsController extends StaticIntervalPollingController
 
   /* istanbul ignore next */
   async #fetch(request: string, options?: RequestInit) {
+    const headers: Record<string, string> = {
+      'Content-Type': 'application/json',
+      ...(this.#clientId && { 'X-Client-Id': this.#clientId }),
+    };
+
+    const urlMatches =
+      request.startsWith(API_BASE_URL) ||
+      Object.values(SENTINEL_API_BASE_URL_MAP).some((baseUrl) =>
+        request.startsWith(baseUrl),
+      );
+    if (this.#getBearerToken && urlMatches) {
+      const token = await Promise.resolve(this.#getBearerToken());
+      if (token) {
+        headers.Authorization = `Bearer ${token}`;
+      }
+    }
+
     const fetchOptions = {
       ...options,
       headers: {
-        'Content-Type': 'application/json',
-        ...(this.#clientId && { 'X-Client-Id': this.#clientId }),
+        ...headers,
+        ...options?.headers,
       },
     };
 
@@ -312,6 +344,7 @@ export class SmartTransactionsController extends StaticIntervalPollingController
     state = {},
     messenger,
     getMetaMetricsProps,
+    getBearerToken,
     trace,
   }: SmartTransactionsControllerOptions) {
     super({
@@ -323,6 +356,7 @@ export class SmartTransactionsController extends StaticIntervalPollingController
         ...state,
       },
     });
+
     this.#interval = interval;
     this.#clientId = clientId;
     this.#chainId = InitialChainId;
@@ -331,6 +365,7 @@ export class SmartTransactionsController extends StaticIntervalPollingController
     this.#ethQuery = undefined;
     this.#trackMetaMetricsEvent = trackMetaMetricsEvent;
     this.#getMetaMetricsProps = getMetaMetricsProps;
+    this.#getBearerToken = getBearerToken;
     this.#trace = trace ?? (((_request, fn) => fn?.()) as TraceCallback);
 
     this.initializeSmartTransactionsForChainId();