diff --git a/types/webidl-conversions/index.d.ts b/types/webidl-conversions/index.d.ts
index fedd3595ef..92919dfe87 100644
--- a/types/webidl-conversions/index.d.ts
+++ b/types/webidl-conversions/index.d.ts
@@ -1,4 +1,4 @@
-// Type definitions for webidl-conversions 4.0
+// Type definitions for webidl-conversions 5.0
 // Project: https://github.com/jsdom/webidl-conversions#readme
 // Definitions by: ExE Boss <https://github.com/ExE-Boss>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
@@ -52,9 +52,7 @@ declare const WebIDLConversions: {
 	ByteString(V: any, opts?: WebIDLConversions.StringOptions): string;
 	USVString(V: any, opts?: WebIDLConversions.StringOptions): string;
 
-	object(V: any, opts?: WebIDLConversions.Options): object;
-	Error(V: any, opts?: WebIDLConversions.Options): Error;
-
+	object<V>(V: V, opts?: WebIDLConversions.Options): V extends object ? V : V & object;
 	ArrayBuffer(V: any, opts?: WebIDLConversions.Options): ArrayBuffer;
 	DataView(V: any, opts?: WebIDLConversions.Options): DataView;
 
diff --git a/types/webidl-conversions/webidl-conversions-tests.ts b/types/webidl-conversions/webidl-conversions-tests.ts
index 3ae2767a93..08719c3d5b 100644
--- a/types/webidl-conversions/webidl-conversions-tests.ts
+++ b/types/webidl-conversions/webidl-conversions-tests.ts
@@ -7,6 +7,12 @@ const options: conversions.Options = ((): conversions.Options => {
 	return {};
 })();
 
+/**
+ * The `expectType` function from https://www.npmjs.com/package/tsd,
+ * except instead of returning `void`, it returns `T`.
+ */
+declare function expectType<T>(value: T): T;
+
 conversions.any(any); // $ExpectType any
 conversions.any(unknown); // $ExpectType unknown
 conversions.any(options); // $ExpectType Options
@@ -38,8 +44,12 @@ conversions.DOMString(any, options); // $ExpectType string
 conversions.ByteString(any, options); // $ExpectType string
 conversions.USVString(any, options); // $ExpectType string
 
-conversions.object(any, options); // $ExpectType object
-conversions.Error(any, options); // $ExpectType Error
+conversions.object(any, options); // $ExpectType any
+conversions.object(unknown, options); // $ExpectType object
+expectType<null & object>(conversions.object(null, options));
+expectType<string & object>(conversions.object('string', options));
+expectType<number & object>(conversions.object(123, options));
+conversions.object({}, options); // $ExpectType {}
 
 conversions.ArrayBuffer(any, options); // $ExpectType ArrayBuffer
 conversions.DataView(any, options); // $ExpectType DataView