diff --git a/src/github-api.ts b/src/github-api.ts
index 8c72c1032..7419d73a8 100644
--- a/src/github-api.ts
+++ b/src/github-api.ts
@@ -151,6 +151,49 @@ export type ReleaseIteratorOptions = ScmReleaseIteratorOptions;
 
 export const MAX_SLEEP_SECONDS = 20;
 export const MAX_ISSUE_BODY_SIZE = 65536;
+const LABEL_ISSUE_NOT_FOUND_MAX_RETRIES = 3;
+const LABEL_ISSUE_NOT_FOUND_INITIAL_DELAY_MS = 1000;
+
+/**
+ * True when GitHub returns 422 because a newly-created issue/PR is not yet
+ * indexed for label mutations (eventual consistency).
+ */
+export function isIssueNotFoundLabelError(err: unknown): boolean {
+  return (
+    err instanceof RequestError &&
+    err.status === 422 &&
+    err.message.includes('Issue not found')
+  );
+}
+
+async function withRetryOnIssueNotFound<T>(
+  fn: () => Promise<T>,
+  logger: Logger,
+  operation: string
+): Promise<T> {
+  let lastError: Error | undefined;
+  for (let attempt = 0; attempt < LABEL_ISSUE_NOT_FOUND_MAX_RETRIES; attempt++) {
+    try {
+      return await fn();
+    } catch (e) {
+      if (
+        !isIssueNotFoundLabelError(e) ||
+        attempt === LABEL_ISSUE_NOT_FOUND_MAX_RETRIES - 1
+      ) {
+        throw e;
+      }
+      lastError = e as Error;
+      const delayMs = LABEL_ISSUE_NOT_FOUND_INITIAL_DELAY_MS * (attempt + 1);
+      logger.warn(
+        `${operation} failed with 422 Issue not found (attempt ${
+          attempt + 1
+        }/${LABEL_ISSUE_NOT_FOUND_MAX_RETRIES}), retrying in ${delayMs}ms...`
+      );
+      await sleepInMs(delayMs);
+    }
+  }
+  throw lastError!;
+}
 
 export class GitHubApi {
   readonly repository: Repository;
@@ -781,12 +824,17 @@ export class GitHubApi {
         return;
       }
       this.logger.debug(`adding labels: ${labels} from issue/pull ${number}`);
-      await this.octokit.issues.addLabels({
-        owner: this.repository.owner,
-        repo: this.repository.repo,
-        issue_number: number,
-        labels,
-      });
+      await withRetryOnIssueNotFound(
+        () =>
+          this.octokit.issues.addLabels({
+            owner: this.repository.owner,
+            repo: this.repository.repo,
+            issue_number: number,
+            labels,
+          }),
+        this.logger,
+        `addIssueLabels(${number})`
+      );
     }
   );
 
diff --git a/test/github-api.ts b/test/github-api.ts
new file mode 100644
index 000000000..cf0fa9187
--- /dev/null
+++ b/test/github-api.ts
@@ -0,0 +1,136 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import * as nock from 'nock';
+import {expect} from 'chai';
+import {afterEach, beforeEach, describe, it} from 'mocha';
+import * as sinon from 'sinon';
+import {RequestError} from '@octokit/request-error';
+
+import {GitHub} from '../src/github';
+import {isIssueNotFoundLabelError} from '../src/github-api';
+import {GitHubAPIError} from '../src/errors';
+
+const fetch = require('node-fetch');
+const sandbox = sinon.createSandbox();
+
+describe('isIssueNotFoundLabelError', () => {
+  it('returns true for 422 with Issue not found', () => {
+    const err = new RequestError('Validation Failed ... Issue not found', {
+      request: {method: 'POST', url: 'https://api.github.com', headers: {}},
+      response: {
+        status: 422,
+        data: {
+          message: 'Validation Failed',
+          errors: [
+            {
+              resource: 'Label',
+              code: 'unprocessable',
+              field: 'data',
+              message: 'Issue not found',
+            },
+          ],
+        },
+        headers: {},
+        url: 'https://api.github.com',
+      },
+    });
+    expect(isIssueNotFoundLabelError(err)).to.be.true;
+  });
+
+  it('returns false for other 422 errors', () => {
+    const err = new RequestError('Validation Failed', {
+      request: {method: 'POST', url: 'https://api.github.com', headers: {}},
+      response: {
+        status: 422,
+        data: {
+          message: 'Validation Failed',
+          errors: [
+            {
+              resource: 'Release',
+              code: 'already_exists',
+              field: 'tag_name',
+            },
+          ],
+        },
+        headers: {},
+        url: 'https://api.github.com',
+      },
+    });
+    expect(isIssueNotFoundLabelError(err)).to.be.false;
+  });
+});
+
+describe('GitHub addIssueLabels retry', () => {
+  let github: GitHub;
+  let clock: sinon.SinonFakeTimers;
+
+  beforeEach(async () => {
+    nock('https://api.github.com/')
+      .get('/repos/fake/fake')
+      .optionally()
+      .reply(200, {default_branch: 'main'});
+    github = await GitHub.create({
+      owner: 'fake',
+      repo: 'fake',
+      defaultBranch: 'main',
+      fetch,
+    });
+    clock = sandbox.useFakeTimers();
+  });
+
+  afterEach(() => {
+    sandbox.restore();
+    nock.cleanAll();
+  });
+
+  const issueNotFound422 = {
+    message: 'Validation Failed',
+    errors: [
+      {
+        resource: 'Label',
+        code: 'unprocessable',
+        field: 'data',
+        message: 'Issue not found',
+      },
+    ],
+  };
+
+  it('retries on 422 Issue not found then succeeds', async () => {
+    const scope = nock('https://api.github.com/')
+      .post('/repos/fake/fake/issues/42/labels', ['autorelease: pending'])
+      .reply(422, issueNotFound422)
+      .post('/repos/fake/fake/issues/42/labels', ['autorelease: pending'])
+      .reply(200, []);
+
+    const promise = github.addIssueLabels(['autorelease: pending'], 42);
+    await clock.tickAsync(1000);
+    await promise;
+    scope.done();
+  });
+
+  it('throws GitHubAPIError after retries are exhausted', async () => {
+    const scope = nock('https://api.github.com/')
+      .post('/repos/fake/fake/issues/42/labels')
+      .times(3)
+      .reply(422, issueNotFound422);
+
+    const promise = github.addIssueLabels(['autorelease: pending'], 42);
+    const assertPromise = expect(promise).to.be.rejectedWith(GitHubAPIError);
+    await clock.tickAsync(1000);
+    await clock.tickAsync(2000);
+    await assertPromise;
+    scope.done();
+  });
+});