diff --git a/api_signaling.go b/api_signaling.go
index 1c48c78..db4036b 100644
--- a/api_signaling.go
+++ b/api_signaling.go
@@ -28,6 +28,7 @@ import (
 	"net/url"
 	"sort"
 	"strings"
+	"time"
 
 	"github.com/golang-jwt/jwt/v4"
 )
@@ -847,6 +848,7 @@ type TransientDataClientMessage struct {
 
 	Key   string           `json:"key,omitempty"`
 	Value *json.RawMessage `json:"value,omitempty"`
+	TTL   time.Duration    `json:"ttl,omitempty"`
 }
 
 func (m *TransientDataClientMessage) CheckValid() error {
diff --git a/backend_server_test.go b/backend_server_test.go
index 82f3ee8..e9d25bd 100644
--- a/backend_server_test.go
+++ b/backend_server_test.go
@@ -626,7 +626,8 @@ func TestBackendServer_RoomDisinviteDifferentRooms(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if _, err := client2.RunUntilHello(ctx); err != nil {
+	hello2, err := client2.RunUntilHello(ctx)
+	if err != nil {
 		t.Fatal(err)
 	}
 
@@ -635,16 +636,14 @@ func TestBackendServer_RoomDisinviteDifferentRooms(t *testing.T) {
 	if _, err := client1.JoinRoom(ctx, roomId1); err != nil {
 		t.Fatal(err)
 	}
+	if err := client1.RunUntilJoined(ctx, hello1.Hello); err != nil {
+		t.Error(err)
+	}
 	roomId2 := "test-room2"
 	if _, err := client2.JoinRoom(ctx, roomId2); err != nil {
 		t.Fatal(err)
 	}
-
-	// Ignore "join" events.
-	if err := client1.DrainMessages(ctx); err != nil {
-		t.Error(err)
-	}
-	if err := client2.DrainMessages(ctx); err != nil {
+	if err := client2.RunUntilJoined(ctx, hello2.Hello); err != nil {
 		t.Error(err)
 	}
 
@@ -702,6 +701,7 @@ func TestBackendServer_RoomDisinviteDifferentRooms(t *testing.T) {
 			UserIds: []string{
 				testDefaultUserId,
 			},
+			Properties: (*json.RawMessage)(&testRoomProperties),
 		},
 	}
 
diff --git a/docs/standalone-signaling-api-v1.md b/docs/standalone-signaling-api-v1.md
index a53dd26..914cf7d 100644
--- a/docs/standalone-signaling-api-v1.md
+++ b/docs/standalone-signaling-api-v1.md
@@ -817,14 +817,17 @@ Message format (Client -> Server):
       "transient": {
         "type": "set",
         "key": "sample-key",
-        "value": "any-json-object"
+        "value": "any-json-object",
+        "ttl": "optional-ttl"
       }
     }
 
 - The `key` must be a string.
 - The `value` can be of any type (i.e. string, number, array, object, etc.).
+- The `ttl` is the time to live in nanoseconds. The value will be removed after
+  that time (if it is still present).
 - Requests to set a value that is already present for the key are silently
-  ignored.
+  ignored. Any TTL value will be updated / removed.
 
 
 Message format (Server -> Client):
diff --git a/hub.go b/hub.go
index ee6b1eb..f7ef8fb 100644
--- a/hub.go
+++ b/hub.go
@@ -1965,9 +1965,9 @@ func (h *Hub) processTransientMsg(client *Client, message *ClientMessage) {
 		}
 
 		if msg.Value == nil {
-			room.SetTransientData(msg.Key, nil)
+			room.SetTransientDataTTL(msg.Key, nil, msg.TTL)
 		} else {
-			room.SetTransientData(msg.Key, *msg.Value)
+			room.SetTransientDataTTL(msg.Key, *msg.Value, msg.TTL)
 		}
 	case "remove":
 		if !isAllowedToUpdateTransientData(session) {
diff --git a/room.go b/room.go
index a4d0e09..e0a533a 100644
--- a/room.go
+++ b/room.go
@@ -1059,6 +1059,10 @@ func (r *Room) SetTransientData(key string, value interface{}) {
 	r.transientData.Set(key, value)
 }
 
+func (r *Room) SetTransientDataTTL(key string, value interface{}, ttl time.Duration) {
+	r.transientData.SetTTL(key, value, ttl)
+}
+
 func (r *Room) RemoveTransientData(key string) {
 	r.transientData.Remove(key)
 }
diff --git a/testclient_test.go b/testclient_test.go
index 2f2fde7..acb64e6 100644
--- a/testclient_test.go
+++ b/testclient_test.go
@@ -578,7 +578,7 @@ func (c *TestClient) SendInternalRemoveSession(msg *RemoveSessionInternalClientM
 	return c.WriteJSON(message)
 }
 
-func (c *TestClient) SetTransientData(key string, value interface{}) error {
+func (c *TestClient) SetTransientData(key string, value interface{}, ttl time.Duration) error {
 	payload, err := json.Marshal(value)
 	if err != nil {
 		c.t.Fatal(err)
@@ -591,6 +591,7 @@ func (c *TestClient) SetTransientData(key string, value interface{}) error {
 			Type:  "set",
 			Key:   key,
 			Value: (*json.RawMessage)(&payload),
+			TTL:   ttl,
 		},
 	}
 	return c.WriteJSON(message)
diff --git a/transient_data.go b/transient_data.go
index 392af02..120a454 100644
--- a/transient_data.go
+++ b/transient_data.go
@@ -24,6 +24,7 @@ package signaling
 import (
 	"reflect"
 	"sync"
+	"time"
 )
 
 type TransientListener interface {
@@ -34,6 +35,8 @@ type TransientData struct {
 	mu        sync.Mutex
 	data      map[string]interface{}
 	listeners map[TransientListener]bool
+	timers    map[string]*time.Timer
+	ttlCh     chan<- struct{}
 }
 
 // NewTransientData creates a new transient data container.
@@ -99,9 +102,59 @@ func (t *TransientData) RemoveListener(listener TransientListener) {
 	delete(t.listeners, listener)
 }
 
+func (t *TransientData) updateTTL(key string, value interface{}, ttl time.Duration) {
+	if ttl <= 0 {
+		delete(t.timers, key)
+	} else {
+		t.removeAfterTTL(key, value, ttl)
+	}
+}
+
+func (t *TransientData) removeAfterTTL(key string, value interface{}, ttl time.Duration) {
+	if ttl <= 0 {
+		return
+	}
+
+	if old, found := t.timers[key]; found {
+		old.Stop()
+	}
+
+	timer := time.AfterFunc(ttl, func() {
+		t.mu.Lock()
+		defer t.mu.Unlock()
+
+		t.compareAndRemove(key, value)
+		if t.ttlCh != nil {
+			select {
+			case t.ttlCh <- struct{}{}:
+			default:
+			}
+		}
+	})
+	if t.timers == nil {
+		t.timers = make(map[string]*time.Timer)
+	}
+	t.timers[key] = timer
+}
+
+func (t *TransientData) doSet(key string, value interface{}, prev interface{}, ttl time.Duration) {
+	if t.data == nil {
+		t.data = make(map[string]interface{})
+	}
+	t.data[key] = value
+	t.notifySet(key, prev, value)
+	t.removeAfterTTL(key, value, ttl)
+}
+
 // Set sets a new value for the given key and notifies listeners
 // if the value has been changed.
 func (t *TransientData) Set(key string, value interface{}) bool {
+	return t.SetTTL(key, value, 0)
+}
+
+// SetTTL sets a new value for the given key with a time-to-live and notifies
+// listeners if the value has been changed.
+func (t *TransientData) SetTTL(key string, value interface{}, ttl time.Duration) bool {
 	if value == nil {
 		return t.Remove(key)
 	}
@@ -111,20 +164,24 @@ func (t *TransientData) Set(key string, value interface{}) bool {
 
 	prev, found := t.data[key]
 	if found && reflect.DeepEqual(prev, value) {
+		t.updateTTL(key, value, ttl)
 		return false
 	}
 
-	if t.data == nil {
-		t.data = make(map[string]interface{})
-	}
-	t.data[key] = value
-	t.notifySet(key, prev, value)
+	t.doSet(key, value, prev, ttl)
 	return true
 }
 
 // CompareAndSet sets a new value for the given key only for a given old value
 // and notifies listeners if the value has been changed.
 func (t *TransientData) CompareAndSet(key string, old, value interface{}) bool {
+	return t.CompareAndSetTTL(key, old, value, 0)
+}
+
+// CompareAndSetTTL sets a new value for the given key with a time-to-live,
+// only for a given old value and notifies listeners if the value has been
+// changed.
+func (t *TransientData) CompareAndSetTTL(key string, old, value interface{}, ttl time.Duration) bool {
 	if value == nil {
 		return t.CompareAndRemove(key, old)
 	}
@@ -139,11 +196,19 @@ func (t *TransientData) CompareAndSet(key string, old, value interface{}) bool {
 		return false
 	}
 
-	t.data[key] = value
-	t.notifySet(key, prev, value)
+	t.doSet(key, value, prev, ttl)
 	return true
 }
 
+func (t *TransientData) doRemove(key string, prev interface{}) {
+	delete(t.data, key)
+	if old, found := t.timers[key]; found {
+		old.Stop()
+		delete(t.timers, key)
+	}
+	t.notifyDeleted(key, prev)
+}
+
 // Remove deletes the value with the given key and notifies listeners
 // if the key was removed.
 func (t *TransientData) Remove(key string) bool {
@@ -155,8 +220,7 @@ func (t *TransientData) Remove(key string) bool {
 		return false
 	}
 
-	delete(t.data, key)
-	t.notifyDeleted(key, prev)
+	t.doRemove(key, prev)
 	return true
 }
 
@@ -166,13 +230,16 @@ func (t *TransientData) CompareAndRemove(key string, old interface{}) bool {
 	t.mu.Lock()
 	defer t.mu.Unlock()
 
+	return t.compareAndRemove(key, old)
+}
+
+func (t *TransientData) compareAndRemove(key string, old interface{}) bool {
 	prev, found := t.data[key]
 	if !found || !reflect.DeepEqual(prev, old) {
 		return false
 	}
 
-	delete(t.data, key)
-	t.notifyDeleted(key, prev)
+	t.doRemove(key, prev)
 	return true
 }
 
diff --git a/transient_data_test.go b/transient_data_test.go
index 598fac2..41ca971 100644
--- a/transient_data_test.go
+++ b/transient_data_test.go
@@ -27,6 +27,13 @@ import (
 	"time"
 )
 
+func (t *TransientData) SetTTLChannel(ch chan<- struct{}) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	t.ttlCh = ch
+}
+
 func Test_TransientData(t *testing.T) {
 	data := NewTransientData()
 	if data.Set("foo", nil) {
@@ -53,6 +60,9 @@ func Test_TransientData(t *testing.T) {
 	if !data.CompareAndSet("test", nil, "123") {
 		t.Errorf("should have set value")
 	}
+	if data.CompareAndSet("test", nil, "456") {
+		t.Errorf("should not have set value")
+	}
 	if data.CompareAndRemove("test", "1234") {
 		t.Errorf("should not have removed value")
 	}
@@ -65,6 +75,61 @@ func Test_TransientData(t *testing.T) {
 	if !data.Remove("foo") {
 		t.Errorf("should have removed value")
 	}
+
+	ttlCh := make(chan struct{})
+	data.SetTTLChannel(ttlCh)
+	if !data.SetTTL("test", "1234", time.Millisecond) {
+		t.Errorf("should have set value")
+	}
+	if value := data.GetData()["test"]; value != "1234" {
+		t.Errorf("expected 1234, got %v", value)
+	}
+	// Data is removed after the TTL
+	<-ttlCh
+	if value := data.GetData()["test"]; value != nil {
+		t.Errorf("expected no value, got %v", value)
+	}
+
+	if !data.SetTTL("test", "1234", time.Millisecond) {
+		t.Errorf("should have set value")
+	}
+	if value := data.GetData()["test"]; value != "1234" {
+		t.Errorf("expected 1234, got %v", value)
+	}
+	if !data.SetTTL("test", "2345", 3*time.Millisecond) {
+		t.Errorf("should have set value")
+	}
+	if value := data.GetData()["test"]; value != "2345" {
+		t.Errorf("expected 2345, got %v", value)
+	}
+	// Data is removed after the TTL only if the value still matches
+	time.Sleep(2 * time.Millisecond)
+	if value := data.GetData()["test"]; value != "2345" {
+		t.Errorf("expected 2345, got %v", value)
+	}
+	// Data is removed after the (second) TTL
+	<-ttlCh
+	if value := data.GetData()["test"]; value != nil {
+		t.Errorf("expected no value, got %v", value)
+	}
+
+	// Setting existing key will update the TTL
+	if !data.SetTTL("test", "1234", time.Millisecond) {
+		t.Errorf("should have set value")
+	}
+	if data.SetTTL("test", "1234", 3*time.Millisecond) {
+		t.Errorf("should not have set value")
+	}
+	// Data still exists after the first TTL
+	time.Sleep(2 * time.Millisecond)
+	if value := data.GetData()["test"]; value != "1234" {
+		t.Errorf("expected 1234, got %v", value)
+	}
+	// Data is removed after the (updated) TTL
+	<-ttlCh
+	if value := data.GetData()["test"]; value != nil {
+		t.Errorf("expected no value, got %v", value)
+	}
 }
 
 func Test_TransientMessages(t *testing.T) {
@@ -83,7 +148,7 @@ func Test_TransientMessages(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err := client1.SetTransientData("foo", "bar"); err != nil {
+	if err := client1.SetTransientData("foo", "bar", 0); err != nil {
 		t.Fatal(err)
 	}
 	if msg, err := client1.RunUntilMessage(ctx); err != nil {
@@ -137,7 +202,7 @@ func Test_TransientMessages(t *testing.T) {
 	// Client 2 may not modify transient data.
 	session2.SetPermissions([]Permission{})
 
-	if err := client2.SetTransientData("foo", "bar"); err != nil {
+	if err := client2.SetTransientData("foo", "bar", 0); err != nil {
 		t.Fatal(err)
 	}
 	if msg, err := client2.RunUntilMessage(ctx); err != nil {
@@ -148,7 +213,7 @@ func Test_TransientMessages(t *testing.T) {
 		}
 	}
 
-	if err := client1.SetTransientData("foo", "bar"); err != nil {
+	if err := client1.SetTransientData("foo", "bar", 0); err != nil {
 		t.Fatal(err)
 	}
 
@@ -179,7 +244,7 @@ func Test_TransientMessages(t *testing.T) {
 	}
 
 	// Setting the same value is ignored by the server.
-	if err := client1.SetTransientData("foo", "bar"); err != nil {
+	if err := client1.SetTransientData("foo", "bar", 0); err != nil {
 		t.Fatal(err)
 	}
 	ctx2, cancel2 := context.WithTimeout(context.Background(), 100*time.Millisecond)
@@ -196,7 +261,7 @@ func Test_TransientMessages(t *testing.T) {
 	data := map[string]interface{}{
 		"hello": "world",
 	}
-	if err := client1.SetTransientData("foo", data); err != nil {
+	if err := client1.SetTransientData("foo", data, 0); err != nil {
 		t.Fatal(err)
 	}
 
@@ -249,7 +314,7 @@ func Test_TransientMessages(t *testing.T) {
 		t.Errorf("Expected no payload, got %+v", msg)
 	}
 
-	if err := client1.SetTransientData("abc", data); err != nil {
+	if err := client1.SetTransientData("abc", data, 10*time.Millisecond); err != nil {
 		t.Fatal(err)
 	}
 
@@ -290,4 +355,11 @@ func Test_TransientMessages(t *testing.T) {
 	}); err != nil {
 		t.Fatal(err)
 	}
+
+	time.Sleep(10 * time.Millisecond)
+	if msg, err = client3.RunUntilMessage(ctx); err != nil {
+		t.Fatal(err)
+	} else if err := checkMessageTransientRemove(msg, "abc", data); err != nil {
+		t.Fatal(err)
+	}
 }