diff --git a/storage/grpc_client.go b/storage/grpc_client.go
index 1274be5f2586..ea56f70065fa 100644
--- a/storage/grpc_client.go
+++ b/storage/grpc_client.go
@@ -550,7 +550,19 @@ func (c *grpcStorageClient) UpdateObject(ctx context.Context, bucket, object str
 	if uattrs.ACL != nil || len(uattrs.PredefinedACL) > 0 {
 		fieldMask.Paths = append(fieldMask.Paths, "acl")
 	}
-	// TODO(cathyo): Handle metadata. Pending b/230510191.
+
+	if uattrs.Metadata != nil {
+		// We don't support deleting a specific metadata key; metadata is deleted
+		// as a whole if provided an empty map, so we do not use dot notation here
+		if len(uattrs.Metadata) == 0 {
+			fieldMask.Paths = append(fieldMask.Paths, "metadata")
+		} else {
+			// We can, however, use dot notation for adding keys
+			for key := range uattrs.Metadata {
+				fieldMask.Paths = append(fieldMask.Paths, fmt.Sprintf("metadata.%s", key))
+			}
+		}
+	}
 
 	req.UpdateMask = fieldMask
 
diff --git a/storage/integration_test.go b/storage/integration_test.go
index e2db30cb4f5c..a557b2a6c20b 100644
--- a/storage/integration_test.go
+++ b/storage/integration_test.go
@@ -1349,7 +1349,8 @@ func TestIntegration_Objects(t *testing.T) {
 }
 
 func TestIntegration_ObjectUpdate(t *testing.T) {
-	multiTransportTest(skipGRPC("metadata pending b/230510191"), t, func(t *testing.T, ctx context.Context, bucket string, _ string, client *Client) {
+	ctx := skipJSONReads(context.Background(), "no reads in test")
+	multiTransportTest(ctx, t, func(t *testing.T, ctx context.Context, bucket string, _ string, client *Client) {
 		b := client.Bucket(bucket)
 
 		o := b.Object("update-obj" + uidSpaceObjects.New())
@@ -1361,11 +1362,11 @@ func TestIntegration_ObjectUpdate(t *testing.T) {
 		if err := w.Close(); err != nil {
 			t.Fatalf("w.Close: %v", err)
 		}
-		t.Cleanup(func() {
+		defer func() {
 			if err := o.Delete(ctx); err != nil {
 				t.Errorf("o.Delete : %v", err)
 			}
-		})
+		}()
 
 		attrs, err := o.Attrs(ctx)
 		if err != nil {
@@ -1401,6 +1402,21 @@ func TestIntegration_ObjectUpdate(t *testing.T) {
 			t.Errorf("updated.Updated should be newer than update.Created")
 		}
 
+		// Add another metadata key
+		anotherKey := map[string]string{"key2": "value2"}
+		metadata["key2"] = "value2"
+
+		updated, err = o.Update(ctx, ObjectAttrsToUpdate{
+			Metadata: anotherKey,
+		})
+		if err != nil {
+			t.Fatalf("o.Update: %v", err)
+		}
+
+		if got, want := updated.Metadata, metadata; !testutil.Equal(got, want) {
+			t.Errorf("updated.Metadata == %+v; want %+v", updated.Metadata, want)
+		}
+
 		// Delete ContentType and ContentLanguage and Metadata.
 		updated, err = o.If(Conditions{MetagenerationMatch: updated.Metageneration}).Update(ctx, ObjectAttrsToUpdate{
 			ContentType:     "",
diff --git a/storage/storage.go b/storage/storage.go
index 2a5723a22ff3..f121823d7722 100644
--- a/storage/storage.go
+++ b/storage/storage.go
@@ -1163,7 +1163,7 @@ func (uattrs *ObjectAttrsToUpdate) toProtoObject(bucket, object string) *storage
 		o.Acl = toProtoObjectACL(uattrs.ACL)
 	}
 
-	// TODO(cathyo): Handle metadata. Pending b/230510191.
+	o.Metadata = uattrs.Metadata
 
 	return o
 }