diff --git a/runtime/factories/android/android.go b/runtime/factories/android/android.go
index 5704786..49c376a 100644
--- a/runtime/factories/android/android.go
+++ b/runtime/factories/android/android.go
@@ -19,6 +19,7 @@
 	"v.io/v23"
 	"v.io/v23/context"
 	"v.io/v23/flow"
+	"v.io/v23/namespace"
 	"v.io/v23/rpc"
 
 	"v.io/x/ref/internal/logger"
@@ -30,6 +31,7 @@
 	"v.io/x/ref/runtime/internal/lib/appcycle"
 	"v.io/x/ref/runtime/internal/lib/roaming"
 	"v.io/x/ref/runtime/internal/lib/xwebsocket"
+	inamespace "v.io/x/ref/runtime/internal/naming/namespace"
 	"v.io/x/ref/runtime/internal/rt"
 	_ "v.io/x/ref/runtime/protocols/tcp"
 	_ "v.io/x/ref/runtime/protocols/ws"
@@ -37,18 +39,29 @@
 	"v.io/x/ref/services/debug/debuglib"
 )
 
+var (
+	commonFlags      *flags.Flags
+	namespaceFactory inamespace.Factory
+)
+
 const (
 	connIdleExpiry = 15 * time.Second
 )
 
-var commonFlags *flags.Flags
-
 func init() {
 	v23.RegisterRuntimeFactory(Init)
 	flow.RegisterUnknownProtocol("wsh", xwebsocket.WSH{})
 	commonFlags = flags.CreateAndRegister(flag.CommandLine, flags.Runtime, flags.Listen)
 }
 
+// Sets the namespace factory to be used for creating all namespaces.
+//
+// If never invoked, a default namespace factory will be used.  If invoked,
+// must be before Init() function below, i.e., before v23.Init().
+func SetNamespaceFactory(factory func(*context.T, namespace.T, ...string) (namespace.T, error)) {
+	namespaceFactory = inamespace.Factory(factory)
+}
+
 func Init(ctx *context.T) (v23.Runtime, *context.T, v23.Shutdown, error) {
 	if err := internal.ParseFlagsAndConfigureGlobalLogger(commonFlags); err != nil {
 		return nil, nil, nil, err
@@ -76,7 +89,7 @@
 
 	publisher := pubsub.NewPublisher()
 
-	runtime, ctx, shutdown, err := rt.Init(ctx, ac, discoveryFactory, nil, &listenSpec, publisher, commonFlags.RuntimeFlags(), reservedDispatcher, connIdleExpiry)
+	runtime, ctx, shutdown, err := rt.Init(ctx, ac, discoveryFactory, namespaceFactory, nil, &listenSpec, publisher, commonFlags.RuntimeFlags(), reservedDispatcher, connIdleExpiry)
 	if err != nil {
 		ishutdown()
 		return nil, nil, nil, err
diff --git a/runtime/factories/chrome/chrome.go b/runtime/factories/chrome/chrome.go
index 9bde6ab..ed49651 100644
--- a/runtime/factories/chrome/chrome.go
+++ b/runtime/factories/chrome/chrome.go
@@ -37,7 +37,7 @@
 
 	protocols := []string{"wsh", "ws"}
 	listenSpec := rpc.ListenSpec{Addrs: rpc.ListenAddrs{{Protocol: "ws", Address: ""}}}
-	runtime, ctx, shutdown, err := grt.Init(ctx, nil, nil, protocols, &listenSpec, nil, commonFlags.RuntimeFlags(), nil, 0)
+	runtime, ctx, shutdown, err := grt.Init(ctx, nil, nil, nil, protocols, &listenSpec, nil, commonFlags.RuntimeFlags(), nil, 0)
 	if err != nil {
 		return nil, nil, nil, err
 	}
diff --git a/runtime/factories/gce/gce.go b/runtime/factories/gce/gce.go
index a28801c..b230fc6 100644
--- a/runtime/factories/gce/gce.go
+++ b/runtime/factories/gce/gce.go
@@ -64,7 +64,7 @@
 		})
 	}
 
-	runtime, ctx, shutdown, err := grt.Init(ctx, ac, nil, nil, &listenSpec, nil, commonFlags.RuntimeFlags(), nil, 0)
+	runtime, ctx, shutdown, err := grt.Init(ctx, ac, nil, nil, nil, &listenSpec, nil, commonFlags.RuntimeFlags(), nil, 0)
 	if err != nil {
 		ac.Shutdown()
 		return nil, nil, nil, err
diff --git a/runtime/factories/generic/generic.go b/runtime/factories/generic/generic.go
index de7c2a6..ac3a0d6 100644
--- a/runtime/factories/generic/generic.go
+++ b/runtime/factories/generic/generic.go
@@ -58,7 +58,7 @@
 		discoveryFactory.Shutdown()
 	}
 
-	runtime, ctx, shutdown, err := grt.Init(ctx, ac, discoveryFactory, nil, &listenSpec, nil, commonFlags.RuntimeFlags(), nil, 0)
+	runtime, ctx, shutdown, err := grt.Init(ctx, ac, discoveryFactory, nil, nil, &listenSpec, nil, commonFlags.RuntimeFlags(), nil, 0)
 	if err != nil {
 		ishutdown()
 		return nil, nil, nil, err
diff --git a/runtime/factories/roaming/roaming.go b/runtime/factories/roaming/roaming.go
index 926e486..e8e6ea3 100644
--- a/runtime/factories/roaming/roaming.go
+++ b/runtime/factories/roaming/roaming.go
@@ -72,7 +72,7 @@
 
 	publisher := pubsub.NewPublisher()
 
-	runtime, ctx, shutdown, err := rt.Init(ctx, ac, discoveryFactory, nil, &listenSpec, publisher, commonFlags.RuntimeFlags(), reservedDispatcher, 0)
+	runtime, ctx, shutdown, err := rt.Init(ctx, ac, discoveryFactory, nil, nil, &listenSpec, publisher, commonFlags.RuntimeFlags(), reservedDispatcher, 0)
 	if err != nil {
 		ishutdown()
 		return nil, nil, nil, err
diff --git a/runtime/internal/naming/namespace/namespace.go b/runtime/internal/naming/namespace/namespace.go
index d02494f..f657b47 100644
--- a/runtime/internal/naming/namespace/namespace.go
+++ b/runtime/internal/naming/namespace/namespace.go
@@ -9,6 +9,7 @@
 	"time"
 
 	"v.io/v23/context"
+	vnamespace "v.io/v23/namespace"
 	"v.io/v23/naming"
 	"v.io/v23/options"
 	"v.io/v23/rpc"
@@ -29,7 +30,7 @@
 	errNotRootedName = verror.Register(pkgPath+".errNotRootedName", verror.NoRetry, "{1:}{2:} At least one root is not a rooted name{:_}")
 )
 
-// namespace is an implementation of naming.Namespace.
+// namespace is an implementation of namespace.T.
 type namespace struct {
 	sync.RWMutex
 
@@ -44,6 +45,10 @@
 	resolutionCache cache
 }
 
+// Factory creates a new namespace given a default namespace and a set
+// of roots.
+type Factory func(*context.T, vnamespace.T, ...string) (vnamespace.T, error)
+
 func rooted(names []string) bool {
 	for _, n := range names {
 		if a, _ := naming.SplitAddressName(n); len(a) == 0 {
@@ -71,7 +76,7 @@
 	}, nil
 }
 
-// SetRoots implements naming.Namespace.SetRoots
+// SetRoots implements namespace.T.SetRoots
 func (ns *namespace) SetRoots(roots ...string) error {
 	defer apilog.LogCallf(nil, "roots...=%v", roots)(nil, "") // gologcop: DO NOT EDIT, MUST BE FIRST STATEMENT
 	// Allow roots to be cleared with a call of SetRoots()
@@ -95,7 +100,7 @@
 	}
 }
 
-// Roots implements naming.Namespace.Roots
+// Roots implements namespace.T.Roots
 func (ns *namespace) Roots() []string {
 	//nologcall
 	ns.RLock()
@@ -182,7 +187,7 @@
 	return ctx
 }
 
-// CacheCtl implements naming.Namespace.CacheCtl
+// CacheCtl implements namespace.T.CacheCtl
 func (ns *namespace) CacheCtl(ctls ...naming.CacheCtl) []naming.CacheCtl {
 	defer apilog.LogCallf(nil, "ctls...=%v", ctls)(nil, "") // gologcop: DO NOT EDIT, MUST BE FIRST STATEMENT
 	for _, c := range ctls {
diff --git a/runtime/internal/rpc/resolve_test.go b/runtime/internal/rpc/resolve_test.go
index 326cfec..e5b1e0a 100644
--- a/runtime/internal/rpc/resolve_test.go
+++ b/runtime/internal/rpc/resolve_test.go
@@ -44,6 +44,7 @@
 		ac,
 		nil,
 		nil,
+		nil,
 		&listenSpec,
 		nil,
 		commonFlags.RuntimeFlags(),
diff --git a/runtime/internal/rt/runtime.go b/runtime/internal/rt/runtime.go
index 0574433..649e15b 100644
--- a/runtime/internal/rt/runtime.go
+++ b/runtime/internal/rt/runtime.go
@@ -66,6 +66,7 @@
 type initData struct {
 	appCycle          v23.AppCycle
 	discoveryFactory  idiscovery.Factory
+	namespaceFactory  inamespace.Factory
 	protocols         []string
 	settingsPublisher *pubsub.Publisher
 	connIdleExpiry    time.Duration
@@ -85,6 +86,7 @@
 	ctx *context.T,
 	appCycle v23.AppCycle,
 	discoveryFactory idiscovery.Factory,
+	namespaceFactory inamespace.Factory,
 	protocols []string,
 	listenSpec *rpc.ListenSpec,
 	settingsPublisher *pubsub.Publisher,
@@ -96,6 +98,7 @@
 	ctx = context.WithValue(ctx, initKey, &initData{
 		appCycle:          appCycle,
 		discoveryFactory:  discoveryFactory,
+		namespaceFactory:  namespaceFactory,
 		protocols:         protocols,
 		settingsPublisher: settingsPublisher,
 		connIdleExpiry:    connIdleExpiry,
@@ -322,18 +325,21 @@
 }
 
 func (r *Runtime) setNewNamespace(ctx *context.T, roots ...string) (*context.T, namespace.T, error) {
-	ns, err := inamespace.New(roots...)
-	if err != nil {
+	id, _ := ctx.Value(initKey).(*initData)
+	var ns namespace.T
+	var err error
+	if ns, err = inamespace.New(roots...); err != nil {
 		return nil, nil, err
 	}
-
+	if id.namespaceFactory != nil {
+		if ns, err = id.namespaceFactory(ctx, ns, roots...); err != nil {
+			return nil, nil, err
+		}
+	}
 	if oldNS := r.GetNamespace(ctx); oldNS != nil {
 		ns.CacheCtl(oldNS.CacheCtl()...)
 	}
-
-	if err == nil {
-		ctx = context.WithValue(ctx, namespaceKey, ns)
-	}
+	ctx = context.WithValue(ctx, namespaceKey, ns)
 	return ctx, ns, err
 }