diff --git a/packages/ts/generator-typescript-plugin-subtypes/src/index.ts b/packages/ts/generator-typescript-plugin-subtypes/src/index.ts
index f78ee4e80c..4f3d64fc79 100644
--- a/packages/ts/generator-typescript-plugin-subtypes/src/index.ts
+++ b/packages/ts/generator-typescript-plugin-subtypes/src/index.ts
@@ -52,6 +52,10 @@ export default class SubTypesPlugin extends Plugin {
             });
           }
         });
+
+        const unionFn = `${convertFullyQualifiedNameToRelativePath(baseKey)}Union.ts`;
+        const unionSource = sources.find(({ fileName }) => fileName === unionFn)!;
+        sources.splice(sources.indexOf(unionSource), 1);
       }
     });
   }
diff --git a/packages/ts/generator-typescript-plugin-subtypes/test/push-type/SubTypes.spec.ts b/packages/ts/generator-typescript-plugin-subtypes/test/push-type/SubTypes.spec.ts
index be43af5bc6..2fa0e01fdd 100644
--- a/packages/ts/generator-typescript-plugin-subtypes/test/push-type/SubTypes.spec.ts
+++ b/packages/ts/generator-typescript-plugin-subtypes/test/push-type/SubTypes.spec.ts
@@ -17,7 +17,7 @@ describe('SubTypesPlugin', () => {
       const generator = createGenerator([BackbonePlugin, ModelPlugin, SubTypesPlugin]);
       const input = await loadInput(sectionName, import.meta.url);
       const files = await generator.process(input);
-      expect(files.length).to.equal(11);
+      expect(files.length).to.equal(10);
 
       const t = await files[1].text();
       expect(t).to.exist;