diff --git a/internal/gatewayapi/listener.go b/internal/gatewayapi/listener.go
index 88667b8ef6d..10c00578d6e 100644
--- a/internal/gatewayapi/listener.go
+++ b/internal/gatewayapi/listener.go
@@ -74,6 +74,7 @@ func (t *Translator) ProcessListeners(gateways []*GatewayContext, xdsIR resource
 			case gwapiv1.UDPProtocolType:
 				t.validateAllowedRoutes(listener, resource.KindUDPRoute)
 			default:
+				listener.SetSupportedKinds(gwapiv1.RouteGroupKind{Kind: "InvalidKind"})
 				status.SetGatewayListenerStatusCondition(listener.gateway.Gateway,
 					listener.listenerStatusIdx,
 					gwapiv1.ListenerConditionAccepted,
diff --git a/internal/gatewayapi/testdata/gateway-with-listener-with-unsupported-protocol.out.yaml b/internal/gatewayapi/testdata/gateway-with-listener-with-unsupported-protocol.out.yaml
index 123a0171cb6..373c2f894ca 100644
--- a/internal/gatewayapi/testdata/gateway-with-listener-with-unsupported-protocol.out.yaml
+++ b/internal/gatewayapi/testdata/gateway-with-listener-with-unsupported-protocol.out.yaml
@@ -34,7 +34,8 @@ gateways:
         status: "True"
         type: ResolvedRefs
       name: unsupported
-      supportedKinds: null
+      supportedKinds:
+      - kind: InvalidKind
 httpRoutes:
 - apiVersion: gateway.networking.k8s.io/v1
   kind: HTTPRoute