diff --git a/x-pack/test/saved_object_api_integration/common/suites/bulk_get.ts b/x-pack/test/saved_object_api_integration/common/suites/bulk_get.ts
index 26a693349496d..abfb1f12a2771 100644
--- a/x-pack/test/saved_object_api_integration/common/suites/bulk_get.ts
+++ b/x-pack/test/saved_object_api_integration/common/suites/bulk_get.ts
@@ -9,12 +9,7 @@ import expect from '@kbn/expect';
 import { SuperTest } from 'supertest';
 import { SAVED_OBJECT_TEST_CASES as CASES } from '../lib/saved_object_test_cases';
 import { SPACES } from '../lib/spaces';
-import {
-  createRequest,
-  expectResponses,
-  getUrlPrefix,
-  getTestTitle,
-} from '../lib/saved_object_test_utils';
+import { expectResponses, getUrlPrefix, getTestTitle } from '../lib/saved_object_test_utils';
 import { ExpectResponseBody, TestCase, TestDefinition, TestSuite } from '../lib/types';
 
 export interface BulkGetTestDefinition extends TestDefinition {
@@ -22,6 +17,7 @@ export interface BulkGetTestDefinition extends TestDefinition {
 }
 export type BulkGetTestSuite = TestSuite<BulkGetTestDefinition>;
 export interface BulkGetTestCase extends TestCase {
+  namespaces?: string[]; // used to define individual "object namespaces" string arrays, e.g., bulkGet across multiple namespaces
   failure?: 400 | 404; // only used for permitted response case
 }
 
@@ -31,6 +27,12 @@ export const TEST_CASES: Record<string, BulkGetTestCase> = Object.freeze({
   DOES_NOT_EXIST,
 });
 
+const createRequest = ({ type, id, namespaces }: BulkGetTestCase) => ({
+  type,
+  id,
+  ...(namespaces && { namespaces }), // individual "object namespaces" string array
+});
+
 export function bulkGetTestSuiteFactory(esArchiver: any, supertest: SuperTest<any>) {
   const expectSavedObjectForbidden = expectResponses.forbiddenTypes('bulk_get');
   const expectResponseBody = (
@@ -49,6 +51,7 @@ export function bulkGetTestSuiteFactory(esArchiver: any, supertest: SuperTest<an
         const object = savedObjects[i];
         const testCase = testCaseArray[i];
         await expectResponses.permitted(object, testCase);
+        // TODO: add assertions for redacted namespaces (this already exists in the bulkCreate test suite)
       }
     }
   };
diff --git a/x-pack/test/saved_object_api_integration/security_and_spaces/apis/bulk_get.ts b/x-pack/test/saved_object_api_integration/security_and_spaces/apis/bulk_get.ts
index d547b95d34f7e..e027e69ccdb1d 100644
--- a/x-pack/test/saved_object_api_integration/security_and_spaces/apis/bulk_get.ts
+++ b/x-pack/test/saved_object_api_integration/security_and_spaces/apis/bulk_get.ts
@@ -5,13 +5,14 @@
  * 2.0.
  */
 
-import { SPACES } from '../../common/lib/spaces';
+import { SPACES, ALL_SPACES_ID } from '../../common/lib/spaces';
 import { testCaseFailures, getTestScenarios } from '../../common/lib/saved_object_test_utils';
 import { TestUser } from '../../common/lib/types';
 import { FtrProviderContext } from '../../common/ftr_provider_context';
 import {
   bulkGetTestSuiteFactory,
   TEST_CASES as CASES,
+  BulkGetTestCase,
   BulkGetTestDefinition,
 } from '../../common/suites/bulk_get';
 
@@ -44,9 +45,26 @@ const createTestCases = (spaceId: string) => {
     CASES.NAMESPACE_AGNOSTIC,
     { ...CASES.DOES_NOT_EXIST, ...fail404() },
   ];
+  const crossNamespace = [
+    {
+      ...CASES.SINGLE_NAMESPACE_SPACE_2,
+      namespaces: ['x', 'y'],
+      ...fail400(), // cannot be searched for in multiple spaces
+    },
+    { ...CASES.SINGLE_NAMESPACE_SPACE_2, namespaces: [SPACE_2_ID] }, // second try searches for it in a single other space, which is valid
+    {
+      ...CASES.MULTI_NAMESPACE_ISOLATED_ONLY_SPACE_1,
+      namespaces: [ALL_SPACES_ID],
+      ...fail400(), // cannot be searched for in multiple spaces
+    },
+    { ...CASES.MULTI_NAMESPACE_ISOLATED_ONLY_SPACE_1, namespaces: [SPACE_1_ID] }, // second try searches for it in a single other space, which is valid
+    { ...CASES.MULTI_NAMESPACE_DEFAULT_AND_SPACE_1, namespaces: [SPACE_2_ID], ...fail404() },
+    { ...CASES.MULTI_NAMESPACE_ALL_SPACES, namespaces: [SPACE_2_ID, 'x'] }, // unknown space is allowed / ignored
+    { ...CASES.MULTI_NAMESPACE_ALL_SPACES, namespaces: [ALL_SPACES_ID] }, // this is different than the same test case in the spaces_only and security_only suites, since MULTI_NAMESPACE_ONLY_SPACE_1 *may* return a 404 error to a partially authorized user
+  ];
   const hiddenType = [{ ...CASES.HIDDEN, ...fail400() }];
-  const allTypes = normalTypes.concat(hiddenType);
-  return { normalTypes, hiddenType, allTypes };
+  const allTypes = [...normalTypes, ...crossNamespace, ...hiddenType];
+  return { normalTypes, crossNamespace, hiddenType, allTypes };
 };
 
 export default function ({ getService }: FtrProviderContext) {
@@ -58,13 +76,39 @@ export default function ({ getService }: FtrProviderContext) {
     supertest
   );
   const createTests = (spaceId: string) => {
-    const { normalTypes, hiddenType, allTypes } = createTestCases(spaceId);
+    const { normalTypes, crossNamespace, hiddenType, allTypes } = createTestCases(spaceId);
     // use singleRequest to reduce execution time and/or test combined cases
+    const authorizedCommon = [
+      createTestDefinitions(normalTypes, false, { singleRequest: true }),
+      createTestDefinitions(hiddenType, true),
+    ].flat();
+
     return {
       unauthorized: createTestDefinitions(allTypes, true),
-      authorized: [
-        createTestDefinitions(normalTypes, false, { singleRequest: true }),
-        createTestDefinitions(hiddenType, true),
+      authorizedAtSpace: [
+        authorizedCommon,
+        ...(() => {
+          const [authorized, unauthorized] = crossNamespace.reduce<
+            [BulkGetTestCase[], BulkGetTestCase[]]
+          >(
+            ([left, right], cur) => {
+              if (cur.namespaces.some((x) => ![ALL_SPACES_ID, spaceId].includes(x))) {
+                return [left, [...right, cur]];
+              }
+              return [[...left, cur], right];
+            },
+            [[], []]
+          );
+          return [
+            ...createTestDefinitions(authorized, false, { singleRequest: true }),
+            ...createTestDefinitions(unauthorized, true),
+          ];
+        })(),
+        createTestDefinitions(allTypes, true, { singleRequest: true }),
+      ].flat(),
+      authorizedEverywhere: [
+        authorizedCommon,
+        createTestDefinitions(crossNamespace, false, { singleRequest: true }),
         createTestDefinitions(allTypes, true, {
           singleRequest: true,
           responseBodyOverride: expectSavedObjectForbidden(['hiddentype']),
@@ -77,7 +121,9 @@ export default function ({ getService }: FtrProviderContext) {
   describe('_bulk_get', () => {
     getTestScenarios().securityAndSpaces.forEach(({ spaceId, users }) => {
       const suffix = ` within the ${spaceId} space`;
-      const { unauthorized, authorized, superuser } = createTests(spaceId);
+      const { unauthorized, authorizedAtSpace, authorizedEverywhere, superuser } = createTests(
+        spaceId
+      );
       const _addTests = (user: TestUser, tests: BulkGetTestDefinition[]) => {
         addTests(`${user.description}${suffix}`, { user, spaceId, tests });
       };
@@ -85,16 +131,15 @@ export default function ({ getService }: FtrProviderContext) {
       [users.noAccess, users.legacyAll, users.allAtOtherSpace].forEach((user) => {
         _addTests(user, unauthorized);
       });
-      [
-        users.dualAll,
-        users.dualRead,
-        users.allGlobally,
-        users.readGlobally,
-        users.allAtSpace,
-        users.readAtSpace,
-      ].forEach((user) => {
-        _addTests(user, authorized);
+
+      [users.allAtSpace, users.readAtSpace].forEach((user) => {
+        _addTests(user, authorizedAtSpace);
       });
+
+      [users.dualAll, users.dualRead, users.allGlobally, users.readGlobally].forEach((user) => {
+        _addTests(user, authorizedEverywhere);
+      });
+
       _addTests(users.superuser, superuser);
     });
   });
diff --git a/x-pack/test/saved_object_api_integration/security_only/apis/bulk_get.ts b/x-pack/test/saved_object_api_integration/security_only/apis/bulk_get.ts
index 18edb7502c65a..4aa722bfc6b07 100644
--- a/x-pack/test/saved_object_api_integration/security_only/apis/bulk_get.ts
+++ b/x-pack/test/saved_object_api_integration/security_only/apis/bulk_get.ts
@@ -5,6 +5,7 @@
  * 2.0.
  */
 
+import { SPACES, ALL_SPACES_ID } from '../../common/lib/spaces';
 import { testCaseFailures, getTestScenarios } from '../../common/lib/saved_object_test_utils';
 import { TestUser } from '../../common/lib/types';
 import { FtrProviderContext } from '../../common/ftr_provider_context';
@@ -14,6 +15,10 @@ import {
   BulkGetTestDefinition,
 } from '../../common/suites/bulk_get';
 
+const {
+  SPACE_1: { spaceId: SPACE_1_ID },
+  SPACE_2: { spaceId: SPACE_2_ID },
+} = SPACES;
 const { fail400, fail404 } = testCaseFailures;
 
 const createTestCases = () => {
@@ -31,6 +36,21 @@ const createTestCases = () => {
     { ...CASES.MULTI_NAMESPACE_ISOLATED_ONLY_SPACE_1, ...fail404() },
     CASES.NAMESPACE_AGNOSTIC,
     { ...CASES.DOES_NOT_EXIST, ...fail404() },
+    {
+      ...CASES.SINGLE_NAMESPACE_SPACE_2,
+      namespaces: ['x', 'y'],
+      ...fail400(), // cannot be searched for in multiple spaces
+    },
+    { ...CASES.SINGLE_NAMESPACE_SPACE_2, namespaces: [SPACE_2_ID] }, // second try searches for it in a single other space, which is valid
+    {
+      ...CASES.MULTI_NAMESPACE_ISOLATED_ONLY_SPACE_1,
+      namespaces: [ALL_SPACES_ID],
+      ...fail400(), // cannot be searched for in multiple spaces
+    },
+    { ...CASES.MULTI_NAMESPACE_ISOLATED_ONLY_SPACE_1, namespaces: [SPACE_1_ID] }, // second try searches for it in a single other space, which is valid
+    { ...CASES.MULTI_NAMESPACE_DEFAULT_AND_SPACE_1, namespaces: [SPACE_2_ID], ...fail404() },
+    { ...CASES.MULTI_NAMESPACE_ALL_SPACES, namespaces: [SPACE_2_ID, 'x'] }, // unknown space is allowed / ignored
+    { ...CASES.MULTI_NAMESPACE_ONLY_SPACE_1, namespaces: [ALL_SPACES_ID] },
   ];
   const hiddenType = [{ ...CASES.HIDDEN, ...fail400() }];
   const allTypes = normalTypes.concat(hiddenType);
diff --git a/x-pack/test/saved_object_api_integration/spaces_only/apis/bulk_get.ts b/x-pack/test/saved_object_api_integration/spaces_only/apis/bulk_get.ts
index e1d0243377b8e..41fa4749cc48e 100644
--- a/x-pack/test/saved_object_api_integration/spaces_only/apis/bulk_get.ts
+++ b/x-pack/test/saved_object_api_integration/spaces_only/apis/bulk_get.ts
@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { SPACES } from '../../common/lib/spaces';
+import { SPACES, ALL_SPACES_ID } from '../../common/lib/spaces';
 import { testCaseFailures, getTestScenarios } from '../../common/lib/saved_object_test_utils';
 import { FtrProviderContext } from '../../common/ftr_provider_context';
 import { bulkGetTestSuiteFactory, TEST_CASES as CASES } from '../../common/suites/bulk_get';
@@ -38,6 +38,21 @@ const createTestCases = (spaceId: string) => [
   CASES.NAMESPACE_AGNOSTIC,
   { ...CASES.HIDDEN, ...fail400() },
   { ...CASES.DOES_NOT_EXIST, ...fail404() },
+  {
+    ...CASES.SINGLE_NAMESPACE_SPACE_2,
+    namespaces: ['x', 'y'],
+    ...fail400(), // cannot be searched for in multiple spaces
+  },
+  { ...CASES.SINGLE_NAMESPACE_SPACE_2, namespaces: [SPACE_2_ID] }, // second try searches for it in a single other space, which is valid
+  {
+    ...CASES.MULTI_NAMESPACE_ISOLATED_ONLY_SPACE_1,
+    namespaces: [ALL_SPACES_ID],
+    ...fail400(), // cannot be searched for in multiple spaces
+  },
+  { ...CASES.MULTI_NAMESPACE_ISOLATED_ONLY_SPACE_1, namespaces: [SPACE_1_ID] }, // second try searches for it in a single other space, which is valid
+  { ...CASES.MULTI_NAMESPACE_DEFAULT_AND_SPACE_1, namespaces: [SPACE_2_ID], ...fail404() },
+  { ...CASES.MULTI_NAMESPACE_ALL_SPACES, namespaces: [SPACE_2_ID, 'x'] }, // unknown space is allowed / ignored
+  { ...CASES.MULTI_NAMESPACE_ONLY_SPACE_1, namespaces: [ALL_SPACES_ID] },
 ];
 
 export default function ({ getService }: FtrProviderContext) {