diff --git a/lib/platform/bitbucket/__snapshots__/index.spec.ts.snap b/lib/platform/bitbucket/__snapshots__/index.spec.ts.snap
index a2e14ba769ec51..8484e51d2693da 100644
--- a/lib/platform/bitbucket/__snapshots__/index.spec.ts.snap
+++ b/lib/platform/bitbucket/__snapshots__/index.spec.ts.snap
@@ -1611,6 +1611,160 @@ Array [
 ]
 `;
 
+exports[`platform/bitbucket/index updatePr() removes inactive reviewers when updating pr 1`] = `
+Array [
+  Object {
+    "headers": Object {
+      "accept": "application/json",
+      "accept-encoding": "gzip, deflate, br",
+      "authorization": "Basic YWJjOjEyMw==",
+      "host": "api.bitbucket.org",
+      "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
+    },
+    "method": "GET",
+    "url": "https://api.bitbucket.org/2.0/repositories/some/repo",
+  },
+  Object {
+    "headers": Object {
+      "accept": "application/json",
+      "accept-encoding": "gzip, deflate, br",
+      "authorization": "Basic YWJjOjEyMw==",
+      "host": "api.bitbucket.org",
+      "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
+    },
+    "method": "GET",
+    "url": "https://api.bitbucket.org/2.0/repositories/some/repo/pullrequests/5",
+  },
+  Object {
+    "body": Object {
+      "description": "body",
+      "reviewers": Array [
+        Object {
+          "account_id": "456",
+          "display_name": "Jane Smith",
+          "uuid": "{90b6646d-1724-4a64-9fd9-539515fe94e9}",
+        },
+        Object {
+          "account_id": "123",
+          "display_name": "Bob Smith",
+          "uuid": "{d2238482-2e9f-48b3-8630-de22ccb9e42f}",
+        },
+      ],
+      "title": "title",
+    },
+    "headers": Object {
+      "accept": "application/json",
+      "accept-encoding": "gzip, deflate, br",
+      "authorization": "Basic YWJjOjEyMw==",
+      "content-length": "245",
+      "content-type": "application/json",
+      "host": "api.bitbucket.org",
+      "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
+    },
+    "method": "PUT",
+    "url": "https://api.bitbucket.org/2.0/repositories/some/repo/pullrequests/5",
+  },
+  Object {
+    "headers": Object {
+      "accept": "application/json",
+      "accept-encoding": "gzip, deflate, br",
+      "authorization": "Basic YWJjOjEyMw==",
+      "host": "api.bitbucket.org",
+      "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
+    },
+    "method": "GET",
+    "url": "https://api.bitbucket.org/2.0/users/456",
+  },
+  Object {
+    "headers": Object {
+      "accept": "application/json",
+      "accept-encoding": "gzip, deflate, br",
+      "authorization": "Basic YWJjOjEyMw==",
+      "host": "api.bitbucket.org",
+      "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
+    },
+    "method": "GET",
+    "url": "https://api.bitbucket.org/2.0/users/123",
+  },
+  Object {
+    "body": Object {
+      "description": "body",
+      "reviewers": Array [
+        Object {
+          "account_id": "456",
+          "display_name": "Jane Smith",
+          "uuid": "{90b6646d-1724-4a64-9fd9-539515fe94e9}",
+        },
+      ],
+      "title": "title",
+    },
+    "headers": Object {
+      "accept": "application/json",
+      "accept-encoding": "gzip, deflate, br",
+      "authorization": "Basic YWJjOjEyMw==",
+      "content-length": "149",
+      "content-type": "application/json",
+      "host": "api.bitbucket.org",
+      "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
+    },
+    "method": "PUT",
+    "url": "https://api.bitbucket.org/2.0/repositories/some/repo/pullrequests/5",
+  },
+]
+`;
+
+exports[`platform/bitbucket/index updatePr() rethrows exception when PR update error not due to inactive reviewers 1`] = `"Response code 400 (Bad Request)"`;
+
+exports[`platform/bitbucket/index updatePr() rethrows exception when PR update error not due to inactive reviewers 2`] = `
+Array [
+  Object {
+    "headers": Object {
+      "accept": "application/json",
+      "accept-encoding": "gzip, deflate, br",
+      "authorization": "Basic YWJjOjEyMw==",
+      "host": "api.bitbucket.org",
+      "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
+    },
+    "method": "GET",
+    "url": "https://api.bitbucket.org/2.0/repositories/some/repo",
+  },
+  Object {
+    "headers": Object {
+      "accept": "application/json",
+      "accept-encoding": "gzip, deflate, br",
+      "authorization": "Basic YWJjOjEyMw==",
+      "host": "api.bitbucket.org",
+      "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
+    },
+    "method": "GET",
+    "url": "https://api.bitbucket.org/2.0/repositories/some/repo/pullrequests/5",
+  },
+  Object {
+    "body": Object {
+      "description": "body",
+      "reviewers": Array [
+        Object {
+          "display_name": "Jane Smith",
+          "uuid": "{90b6646d-1724-4a64-9fd9-539515fe94e9}",
+        },
+      ],
+      "title": "title",
+    },
+    "headers": Object {
+      "accept": "application/json",
+      "accept-encoding": "gzip, deflate, br",
+      "authorization": "Basic YWJjOjEyMw==",
+      "content-length": "130",
+      "content-type": "application/json",
+      "host": "api.bitbucket.org",
+      "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
+    },
+    "method": "PUT",
+    "url": "https://api.bitbucket.org/2.0/repositories/some/repo/pullrequests/5",
+  },
+]
+`;
+
 exports[`platform/bitbucket/index updatePr() throws an error on failure to get current list of reviewers 1`] = `"Response code 500 (Internal Server Error)"`;
 
 exports[`platform/bitbucket/index updatePr() throws an error on failure to get current list of reviewers 2`] = `
diff --git a/lib/platform/bitbucket/index.spec.ts b/lib/platform/bitbucket/index.spec.ts
index 4716c77ab5e5f7..27b42e88955f9a 100644
--- a/lib/platform/bitbucket/index.spec.ts
+++ b/lib/platform/bitbucket/index.spec.ts
@@ -765,6 +765,69 @@ describe('platform/bitbucket/index', () => {
       await bitbucket.updatePr({ number: 5, prTitle: 'title', prBody: 'body' });
       expect(httpMock.getTrace()).toMatchSnapshot();
     });
+    it('removes inactive reviewers when updating pr', async () => {
+      const inactiveReviewer = {
+        display_name: 'Bob Smith',
+        uuid: '{d2238482-2e9f-48b3-8630-de22ccb9e42f}',
+        account_id: '123',
+      };
+      const activeReviewer = {
+        display_name: 'Jane Smith',
+        uuid: '{90b6646d-1724-4a64-9fd9-539515fe94e9}',
+        account_id: '456',
+      };
+      const scope = await initRepoMock();
+      scope
+        .get('/2.0/repositories/some/repo/pullrequests/5')
+        .reply(200, { reviewers: [activeReviewer, inactiveReviewer] })
+        .put('/2.0/repositories/some/repo/pullrequests/5')
+        .reply(400, {
+          type: 'error',
+          error: {
+            fields: {
+              reviewers: ['Malformed reviewers list'],
+            },
+            message: 'reviewers: Malformed reviewers list',
+          },
+        })
+        .get('/2.0/users/123')
+        .reply(200, {
+          account_status: 'inactive',
+        })
+        .get('/2.0/users/456')
+        .reply(200, {
+          account_status: 'active',
+        })
+        .put('/2.0/repositories/some/repo/pullrequests/5')
+        .reply(200);
+      await bitbucket.updatePr({ number: 5, prTitle: 'title', prBody: 'body' });
+      expect(httpMock.getTrace()).toMatchSnapshot();
+    });
+    it('rethrows exception when PR update error not due to inactive reviewers', async () => {
+      const reviewer = {
+        display_name: 'Jane Smith',
+        uuid: '{90b6646d-1724-4a64-9fd9-539515fe94e9}',
+      };
+
+      const scope = await initRepoMock();
+      scope
+        .get('/2.0/repositories/some/repo/pullrequests/5')
+        .reply(200, { reviewers: [reviewer] })
+        .put('/2.0/repositories/some/repo/pullrequests/5')
+        .reply(400, {
+          type: 'error',
+          error: {
+            fields: {
+              reviewers: ['Some other unhandled error'],
+            },
+            message: 'Some other unhandled error',
+          },
+        });
+      await expect(() =>
+        bitbucket.updatePr({ number: 5, prTitle: 'title', prBody: 'body' })
+      ).rejects.toThrowErrorMatchingSnapshot();
+      expect(httpMock.getTrace()).toMatchSnapshot();
+    });
     it('throws an error on failure to get current list of reviewers', async () => {
       const scope = await initRepoMock();
       scope
diff --git a/lib/platform/bitbucket/index.ts b/lib/platform/bitbucket/index.ts
index 04ff05b3cd90de..aca5adc95bf1e4 100644
--- a/lib/platform/bitbucket/index.ts
+++ b/lib/platform/bitbucket/index.ts
@@ -30,7 +30,13 @@ import { smartTruncate } from '../utils/pr-body';
 import { readOnlyIssueBody } from '../utils/read-only-issue-body';
 import * as comments from './comments';
 import * as utils from './utils';
-import { PrResponse, RepoInfoBody, mergeBodyTransformer } from './utils';
+import {
+  PrResponse,
+  PrReviewer,
+  RepoInfoBody,
+  UserResponse,
+  mergeBodyTransformer,
+} from './utils';
 
 const bitbucketHttp = new BitbucketHttp();
 
@@ -712,16 +718,57 @@ export async function updatePr({
     )
   ).body;
 
-  await bitbucketHttp.putJson(
-    `/2.0/repositories/${config.repository}/pullrequests/${prNo}`,
-    {
-      body: {
-        title,
-        description: sanitize(description),
-        reviewers: pr.reviewers,
-      },
+  try {
+    await bitbucketHttp.putJson(
+      `/2.0/repositories/${config.repository}/pullrequests/${prNo}`,
+      {
+        body: {
+          title,
+          description: sanitize(description),
+          reviewers: pr.reviewers,
+        },
+      }
+    );
+  } catch (err) {
+    if (
+      err.statusCode === 400 &&
+      err.body?.error?.message.includes('reviewers: Malformed reviewers list')
+    ) {
+      logger.warn(
+        { err },
+        'PR contains inactive reviewer accounts.  Will try setting only active reviewers'
+      );
+
+      // Bitbucket returns a 400 if any of the PR reviewer accounts are now inactive (ie: disabled/suspended)
+      const activeReviewers: PrReviewer[] = [];
+
+      // Validate that each previous PR reviewer account is still active
+      for (const reviewer of pr.reviewers) {
+        const reviewerUser = (
+          await bitbucketHttp.getJson<UserResponse>(
+            `/2.0/users/${reviewer.account_id}`
+          )
+        ).body;
+
+        if (reviewerUser.account_status === 'active') {
+          activeReviewers.push(reviewer);
+        }
+      }
+
+      await bitbucketHttp.putJson(
+        `/2.0/repositories/${config.repository}/pullrequests/${prNo}`,
+        {
+          body: {
+            title,
+            description: sanitize(description),
+            reviewers: activeReviewers,
+          },
+        }
+      );
+    } else {
+      throw err;
     }
-  );
+  }
 
   if (state === PrState.Closed && pr) {
     await bitbucketHttp.postJson(
diff --git a/lib/platform/bitbucket/utils.ts b/lib/platform/bitbucket/utils.ts
index c20b2ec28c9239..b68e42b63b2ec7 100644
--- a/lib/platform/bitbucket/utils.ts
+++ b/lib/platform/bitbucket/utils.ts
@@ -190,7 +190,7 @@ export interface PrResponse {
       name: string;
     };
   };
-  reviewers: Array<any>;
+  reviewers: Array<PrReviewer>;
   created_on: string;
 }
 
@@ -208,3 +208,16 @@ export function prInfo(pr: PrResponse): Pr {
     createdAt: pr.created_on,
   };
 }
+
+export interface UserResponse {
+  display_name: string;
+  account_id: string;
+  nickname: string;
+  account_status: string;
+}
+
+export interface PrReviewer {
+  display_name: string;
+  account_id: string;
+  nickname: string;
+}