diff --git a/plugins/catalog-backend/src/modules/core/BuiltinKindsEntityProcessor.test.ts b/plugins/catalog-backend/src/modules/core/BuiltinKindsEntityProcessor.test.ts
index dbb9922fe0..e0368d40a6 100644
--- a/plugins/catalog-backend/src/modules/core/BuiltinKindsEntityProcessor.test.ts
+++ b/plugins/catalog-backend/src/modules/core/BuiltinKindsEntityProcessor.test.ts
@@ -418,12 +418,13 @@ describe('BuiltinKindsEntityProcessor', () => {
         metadata: { name: 'n' },
         spec: {
           owner: 'o',
+          subdomainOf: 'p',
         },
       };
 
       await processor.postProcessEntity(entity, location, emit);
 
-      expect(emit).toHaveBeenCalledTimes(2);
+      expect(emit).toHaveBeenCalledTimes(4);
       expect(emit).toHaveBeenCalledWith({
         type: 'relation',
         relation: {
@@ -440,6 +441,22 @@ describe('BuiltinKindsEntityProcessor', () => {
           target: { kind: 'Group', namespace: 'default', name: 'o' },
         },
       });
+      expect(emit).toHaveBeenCalledWith({
+        type: 'relation',
+        relation: {
+          source: { kind: 'Domain', namespace: 'default', name: 'n' },
+          type: 'partOf',
+          target: { kind: 'Domain', namespace: 'default', name: 'p' },
+        },
+      });
+      expect(emit).toHaveBeenCalledWith({
+        type: 'relation',
+        relation: {
+          source: { kind: 'Domain', namespace: 'default', name: 'p' },
+          type: 'hasPart',
+          target: { kind: 'Domain', namespace: 'default', name: 'n' },
+        },
+      });
     });
 
     it('generates relations for user entities', async () => {
diff --git a/plugins/catalog-backend/src/modules/core/BuiltinKindsEntityProcessor.ts b/plugins/catalog-backend/src/modules/core/BuiltinKindsEntityProcessor.ts
index 4dbb23addc..c9ea0dbdc1 100644
--- a/plugins/catalog-backend/src/modules/core/BuiltinKindsEntityProcessor.ts
+++ b/plugins/catalog-backend/src/modules/core/BuiltinKindsEntityProcessor.ts
@@ -298,6 +298,12 @@ export class BuiltinKindsEntityProcessor implements CatalogProcessor {
         RELATION_OWNED_BY,
         RELATION_OWNER_OF,
       );
+      doEmit(
+        domain.spec.subdomainOf,
+        { defaultKind: 'Domain', defaultNamespace: selfRef.namespace },
+        RELATION_PART_OF,
+        RELATION_HAS_PART,
+      );
     }
 
     return entity;