diff --git a/kubernetes/client.go b/kubernetes/client.go
index d6a6185..d52e4c6 100644
--- a/kubernetes/client.go
+++ b/kubernetes/client.go
@@ -39,7 +39,10 @@
 // The provided host is an url (scheme://hostname[:port]) of a
 // Kubernetes master without any path.
 // The provided client is an authorized http.Client used to perform requests to the Kubernetes API master.
-func NewClient(baseURL string, client *http.Client) (*Client, error) {
+func NewClient(baseURL, namespace string, client *http.Client) (*Client, error) {
+	if namespace == "" {
+		return nil, fmt.Errorf("must specify Kubernetes namespace")
+	}
 	validURL, err := url.Parse(baseURL)
 	if err != nil {
 		return nil, fmt.Errorf("failed to parse URL %q: %v", baseURL, err)
@@ -47,7 +50,7 @@
 	return &Client{
 		endpointURL: strings.TrimSuffix(validURL.String(), "/") + "/api/v1",
 		httpClient:  client,
-		namespace:   "default",
+		namespace:   namespace,
 	}, nil
 }
 
diff --git a/kubernetes/client_test.go b/kubernetes/client_test.go
index debf7f5..3deabdc 100644
--- a/kubernetes/client_test.go
+++ b/kubernetes/client_test.go
@@ -74,7 +74,7 @@
 	s := httptest.NewServer(&hs)
 	defer s.Close()
 
-	c, err := kubernetes.NewClient(s.URL, http.DefaultClient)
+	c, err := kubernetes.NewClient(s.URL, "default", http.DefaultClient)
 	if err != nil {
 		t.Fatalf("NewClient: %v", err)
 	}
diff --git a/kubernetes/gke/gke.go b/kubernetes/gke/gke.go
index 0811b53..a7ab1ac 100644
--- a/kubernetes/gke/gke.go
+++ b/kubernetes/gke/gke.go
@@ -35,6 +35,7 @@
 	Project     string
 	TokenSource oauth2.TokenSource
 	Zone        string
+	Namespace   string
 }
 
 type clientOptFunc func(*clientOpt)
@@ -69,9 +70,16 @@
 	})
 }
 
+// OptNamespace sets the Kubernetes namespace to look in.
+func OptNamespace(namespace string) ClientOpt {
+	return clientOptFunc(func(o *clientOpt) {
+		o.Namespace = namespace
+	})
+}
+
 // NewClient returns an Kubernetes client to a GKE cluster.
 func NewClient(ctx context.Context, clusterName string, opts ...ClientOpt) (*kubernetes.Client, error) {
-	var opt clientOpt
+	opt := clientOpt{Namespace: "default"}
 	for _, o := range opts {
 		o.modify(&opt)
 	}
@@ -166,7 +174,7 @@
 		},
 	}
 
-	kubeClient, err := kubernetes.NewClient("https://"+cluster.Endpoint, kubeHTTPClient)
+	kubeClient, err := kubernetes.NewClient("https://"+cluster.Endpoint, opt.Namespace, kubeHTTPClient)
 	if err != nil {
 		return nil, fmt.Errorf("kubernetes HTTP client could not be created: %v", err)
 	}