diff --git a/dev-infra/ng-dev.js b/dev-infra/ng-dev.js
index c7a0b9f07c..ab87dd41df 100755
--- a/dev-infra/ng-dev.js
+++ b/dev-infra/ng-dev.js
@@ -899,9 +899,7 @@ function getVersionForVersionBranch(branchName) {
  */
 function getBranchesForMajorVersions(repo, majorVersions) {
     return tslib.__awaiter(this, void 0, void 0, function* () {
-        // TODO(alxhub): actually paginate this, since eventually the number of branches we have will run
-        // off the end of the first page of data returned by `listBranches`.
-        const { data: branchData } = yield repo.api.repos.listBranches({ owner: repo.owner, repo: repo.name, protected: true, per_page: 100 });
+        const branchData = yield repo.api.paginate(repo.api.repos.listBranches, { owner: repo.owner, repo: repo.name, protected: true });
         const branches = [];
         for (const { name } of branchData) {
             if (!isVersionBranch(name)) {
diff --git a/dev-infra/pr/merge/BUILD.bazel b/dev-infra/pr/merge/BUILD.bazel
index 5781497c84..8a8c21bada 100644
--- a/dev-infra/pr/merge/BUILD.bazel
+++ b/dev-infra/pr/merge/BUILD.bazel
@@ -38,6 +38,7 @@ ts_library(
         "//dev-infra/release/config",
         "//dev-infra/release/versioning",
         "//dev-infra/utils",
+        "//dev-infra/utils/testing",
         "@npm//@types/jasmine",
         "@npm//@types/node",
         "@npm//@types/node-fetch",
diff --git a/dev-infra/pr/merge/defaults/integration.spec.ts b/dev-infra/pr/merge/defaults/integration.spec.ts
index 86959094ff..83a86bb2a8 100644
--- a/dev-infra/pr/merge/defaults/integration.spec.ts
+++ b/dev-infra/pr/merge/defaults/integration.spec.ts
@@ -7,12 +7,14 @@
  */
 
 import * as nock from 'nock';
+import {ParsedUrlQuery} from 'querystring';
 
 import {ReleaseConfig} from '../../../release/config/index';
 import {_npmPackageInfoCache, NpmPackageInfo} from '../../../release/versioning/npm-registry';
 import {GithubConfig} from '../../../utils/config';
 import * as console from '../../../utils/console';
 import {GithubClient} from '../../../utils/git/github';
+import {buildGithubPaginationResponseHeader} from '../../../utils/testing/github-pagination-header';
 import {TargetLabel} from '../config';
 import {getBranchesFromTargetLabel, getTargetLabelFromPullRequest} from '../target-label';
 
@@ -79,7 +81,35 @@ describe('default target labels', () => {
     nock(getRepoApiRequestUrl())
         .get('/branches')
         .query(true)
-        .reply(200, branches.map(name => ({name})));
+        .reply(200, branches.slice(0, 29).map(name => ({name})));
+  }
+
+  /**
+   * Mocks a repository branch list API request with pagination.
+   * https://docs.github.com/en/rest/guides/traversing-with-pagination.
+   * https://docs.github.com/en/rest/reference/repos#list-branches.
+   */
+  function interceptBranchesListRequestWithPagination(branches: string[]) {
+    const apiUrl = getRepoApiRequestUrl();
+
+    // For each branch, create its own API page so that pagination is required
+    // to resolve all given branches.
+    for (let index = 0; index < branches.length; index++) {
+      // Pages start with `1` as per the Github API specification.
+      const pageNum = index + 1;
+      const name = branches[index];
+      const linkHeader =
+          buildGithubPaginationResponseHeader(branches.length, pageNum, `${apiUrl}/branches`);
+
+      // For the first page, either `?page=1` needs to be set, or no `page` should be specified.
+      const queryMatch = pageNum === 1 ?
+          (params: ParsedUrlQuery) => params.page === '1' || params.page === undefined :
+          {page: pageNum};
+
+      nock(getRepoApiRequestUrl()).get('/branches').query(queryMatch).reply(200, [{name}], {
+        link: linkHeader,
+      });
+    }
   }
 
   async function getBranchesForLabel(
@@ -99,7 +129,12 @@ describe('default target labels', () => {
   it('should detect "master" as branch for target: minor', async () => {
     interceptBranchVersionRequest('master', '11.0.0-next.0');
     interceptBranchVersionRequest('10.2.x', '10.2.4');
-    interceptBranchesListRequest(['10.2.x']);
+
+    // Note: We add a few more branches here to ensure that branches API requests are
+    // paginated properly. In Angular projects, there are usually many branches so that
+    // pagination is ultimately needed to detect the active release trains.
+    // See: https://github.com/angular/angular/commit/261b060fa168754db00248d1c5c9574bb19a72b4.
+    interceptBranchesListRequestWithPagination(['9.8.x', '10.1.x', '10.2.x']);
 
     expect(await getBranchesForLabel('target: minor')).toEqual(['master']);
   });
diff --git a/dev-infra/release/versioning/version-branches.ts b/dev-infra/release/versioning/version-branches.ts
index 834210aceb..5f47dc117b 100644
--- a/dev-infra/release/versioning/version-branches.ts
+++ b/dev-infra/release/versioning/version-branches.ts
@@ -72,10 +72,8 @@ export function getVersionForVersionBranch(branchName: string): semver.SemVer|nu
  */
 export async function getBranchesForMajorVersions(
     repo: GithubRepoWithApi, majorVersions: number[]): Promise<VersionBranch[]> {
-  // TODO(alxhub): actually paginate this, since eventually the number of branches we have will run
-  // off the end of the first page of data returned by `listBranches`.
-  const {data: branchData} = await repo.api.repos.listBranches(
-      {owner: repo.owner, repo: repo.name, protected: true, per_page: 100});
+  const branchData = await repo.api.paginate(
+      repo.api.repos.listBranches, {owner: repo.owner, repo: repo.name, protected: true});
   const branches: VersionBranch[] = [];
 
   for (const {name} of branchData) {
diff --git a/dev-infra/utils/testing/github-pagination-header.ts b/dev-infra/utils/testing/github-pagination-header.ts
new file mode 100644
index 0000000000..094250cbf5
--- /dev/null
+++ b/dev-infra/utils/testing/github-pagination-header.ts
@@ -0,0 +1,28 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+/**
+ * Builds the `Link` response header to indicate an API response that is suitable
+ * for pagination. This follows the specification as outlined within:
+ * https://docs.github.com/en/rest/guides/traversing-with-pagination
+ */
+export function buildGithubPaginationResponseHeader(
+    totalPages: number, currentPage: number, baseUrl: string) {
+  const links = [`<${baseUrl}?page=1>; rel="first"`, `<${baseUrl}?page=${totalPages}>; rel="last"`];
+
+  if (currentPage < totalPages) {
+    links.push(`<${baseUrl}?page=${currentPage + 1}>; rel="next"`);
+  }
+
+  // Pages start with `1` as per the Github API specification.
+  if (currentPage > 1) {
+    links.push(`<${baseUrl}?page=${currentPage - 1}>; rel="prev"`);
+  }
+
+  return links.join(',');
+}