diff --git a/src/cdk/schematics/ng-update/upgrade-rules/project-tsconfig-paths.spec.ts b/src/cdk/schematics/ng-update/upgrade-rules/project-tsconfig-paths.spec.ts
index 8008dc9c64ca..cfb52dc1fc58 100644
--- a/src/cdk/schematics/ng-update/upgrade-rules/project-tsconfig-paths.spec.ts
+++ b/src/cdk/schematics/ng-update/upgrade-rules/project-tsconfig-paths.spec.ts
@@ -45,4 +45,24 @@ describe('ng-update project-tsconfig-paths', () => {
 
     expect(getProjectTsConfigPaths(testTree)).toEqual(['tsconfig.json']);
   });
+
+  it('should be able to read workspace configuration which is using JSON5 features', () => {
+    testTree.create('/my-build-config.json', '');
+    testTree.create('/angular.json', `{
+      // Comments, unquoted properties or trailing commas are only supported in JSON5.
+      projects: {
+        with_tests: {
+          targets: {
+            build: {
+              options: {
+                tsConfig: './my-build-config.json',
+              }
+            }
+          }
+        }
+      },
+    }`);
+
+    expect(getProjectTsConfigPaths(testTree)).toEqual(['my-build-config.json']);
+  });
 });
diff --git a/src/cdk/schematics/ng-update/upgrade-rules/project-tsconfig-paths.ts b/src/cdk/schematics/ng-update/upgrade-rules/project-tsconfig-paths.ts
index 0aa9164f6eda..0cc0700520a9 100644
--- a/src/cdk/schematics/ng-update/upgrade-rules/project-tsconfig-paths.ts
+++ b/src/cdk/schematics/ng-update/upgrade-rules/project-tsconfig-paths.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {normalize} from '@angular-devkit/core';
+import {JsonParseMode, normalize, parseJson} from '@angular-devkit/core';
 import {Tree} from '@angular-devkit/schematics';
 
 /** Name of the default Angular CLI workspace configuration files. */
@@ -63,7 +63,9 @@ function getWorkspaceConfigGracefully(tree: Tree): any {
   }
 
   try {
-    return JSON.parse(configBuffer.toString());
+    // Parse the workspace file as JSON5 which is also supported for CLI
+    // workspace configurations.
+    return parseJson(configBuffer.toString(), JsonParseMode.Json5);
   } catch {
     return null;
   }