diff --git a/src/utilities/__tests__/buildASTSchema.js b/src/utilities/__tests__/buildASTSchema.js
index 6de1556e7e..79c35cbcb1 100644
--- a/src/utilities/__tests__/buildASTSchema.js
+++ b/src/utilities/__tests__/buildASTSchema.js
@@ -253,6 +253,40 @@ type Mutation {
     var output = cycleOutput(body, 'HelloScalars', 'Mutation');
     expect(output).to.equal(body);
   });
+
+  it('Unreferenced type implementing referenced interface', () => {
+    var body = `
+type Concrete implements Iface {
+  key: String
+}
+
+interface Iface {
+  key: String
+}
+
+type Query {
+  iface: Iface
+}
+`;
+    var output = cycleOutput(body, 'Query');
+    expect(output).to.equal(body);
+  });
+
+  it('Unreferenced type implementing referenced union', () => {
+    var body = `
+type Concrete {
+  key: String
+}
+
+type Query {
+  union: Union
+}
+
+union Union = Concrete
+`;
+    var output = cycleOutput(body, 'Query');
+    expect(output).to.equal(body);
+  });
 });
 
 describe('Schema Parser Failures', () => {
diff --git a/src/utilities/buildASTSchema.js b/src/utilities/buildASTSchema.js
index 433151d941..dfe64e713d 100644
--- a/src/utilities/buildASTSchema.js
+++ b/src/utilities/buildASTSchema.js
@@ -140,13 +140,14 @@ export function buildASTSchema(
     };
   }
 
-
   var produceTypeDef = getTypeDefProducer(ast);
 
   if (isNullish(astMap[queryTypeName])) {
     throw new Error(`Type ${queryTypeName} not found in document`);
   }
 
+  ast.definitions.forEach(produceTypeDef);
+
   var queryType = produceTypeDef(astMap[queryTypeName]);
   var schema;
   if (isNullish(mutationTypeName)) {