diff --git a/packages/catalog-model/src/kinds/relations.ts b/packages/catalog-model/src/kinds/relations.ts
index 3d5d629b9e..78bbc61df2 100644
--- a/packages/catalog-model/src/kinds/relations.ts
+++ b/packages/catalog-model/src/kinds/relations.ts
@@ -55,3 +55,10 @@ export const RELATION_CHILD_OF = 'childOf';
  */
 export const RELATION_MEMBER_OF = 'memberOf';
 export const RELATION_HAS_MEMBER = 'hasMember';
+
+/**
+ * A part/whole relation, typically for components in a system and systems
+ * in a domain.
+ */
+export const RELATION_PART_OF = 'partOf';
+export const RELATION_HAS_PART = 'hasPart';
diff --git a/plugins/catalog-backend/src/ingestion/processors/BuiltinKindsEntityProcessor.test.ts b/plugins/catalog-backend/src/ingestion/processors/BuiltinKindsEntityProcessor.test.ts
index 94a08c5e73..1d2562c25b 100644
--- a/plugins/catalog-backend/src/ingestion/processors/BuiltinKindsEntityProcessor.test.ts
+++ b/plugins/catalog-backend/src/ingestion/processors/BuiltinKindsEntityProcessor.test.ts
@@ -38,6 +38,7 @@ describe('BuiltinKindsEntityProcessor', () => {
         spec: {
           type: 'service',
           owner: 'o',
+          subcomponentOf: 's',
           lifecycle: 'l',
           providesApis: ['b'],
           consumesApis: ['c'],
@@ -46,7 +47,7 @@ describe('BuiltinKindsEntityProcessor', () => {
 
       await processor.postProcessEntity(entity, location, emit);
 
-      expect(emit).toBeCalledTimes(6);
+      expect(emit).toBeCalledTimes(8);
       expect(emit).toBeCalledWith({
         type: 'relation',
         relation: {
@@ -95,6 +96,22 @@ describe('BuiltinKindsEntityProcessor', () => {
           target: { kind: 'API', namespace: 'default', name: 'c' },
         },
       });
+      expect(emit).toBeCalledWith({
+        type: 'relation',
+        relation: {
+          source: { kind: 'Component', namespace: 'default', name: 's' },
+          type: 'hasPart',
+          target: { kind: 'Component', namespace: 'default', name: 'n' },
+        },
+      });
+      expect(emit).toBeCalledWith({
+        type: 'relation',
+        relation: {
+          source: { kind: 'Component', namespace: 'default', name: 'n' },
+          type: 'partOf',
+          target: { kind: 'Component', namespace: 'default', name: 's' },
+        },
+      });
     });
 
     it('generates relations for api entities', async () => {
diff --git a/plugins/catalog-backend/src/ingestion/processors/BuiltinKindsEntityProcessor.ts b/plugins/catalog-backend/src/ingestion/processors/BuiltinKindsEntityProcessor.ts
index 6cbec5d655..67e89ac52c 100644
--- a/plugins/catalog-backend/src/ingestion/processors/BuiltinKindsEntityProcessor.ts
+++ b/plugins/catalog-backend/src/ingestion/processors/BuiltinKindsEntityProcessor.ts
@@ -32,6 +32,8 @@ import {
   RELATION_CONSUMES_API,
   RELATION_HAS_MEMBER,
   RELATION_MEMBER_OF,
+  RELATION_HAS_PART,
+  RELATION_PART_OF,
   RELATION_OWNED_BY,
   RELATION_OWNER_OF,
   RELATION_PARENT_OF,
@@ -115,6 +117,12 @@ export class BuiltinKindsEntityProcessor implements CatalogProcessor {
         RELATION_OWNED_BY,
         RELATION_OWNER_OF,
       );
+      doEmit(
+        component.spec.subcomponentOf,
+        { defaultKind: 'Component', defaultNamespace: selfRef.namespace },
+        RELATION_PART_OF,
+        RELATION_HAS_PART,
+      );
       doEmit(
         component.spec.providesApis,
         { defaultKind: 'API', defaultNamespace: selfRef.namespace },