diff --git a/pkg/provider/kubernetes/gateway/fixtures/httproute/with_app_protocol_service.yml b/pkg/provider/kubernetes/gateway/fixtures/httproute/with_app_protocol_service.yml
index c364c8f52..4f51360a0 100644
--- a/pkg/provider/kubernetes/gateway/fixtures/httproute/with_app_protocol_service.yml
+++ b/pkg/provider/kubernetes/gateway/fixtures/httproute/with_app_protocol_service.yml
@@ -59,3 +59,13 @@ spec:
           weight: 1
           kind: Service
           group: ""
+        - name: whoami-HTTP
+          port: 80
+          weight: 1
+          kind: Service
+          group: ""
+        - name: whoami-HTTPS
+          port: 443
+          weight: 1
+          kind: Service
+          group: ""
diff --git a/pkg/provider/kubernetes/gateway/fixtures/services.yml b/pkg/provider/kubernetes/gateway/fixtures/services.yml
index 2f864c2f5..143dc8656 100644
--- a/pkg/provider/kubernetes/gateway/fixtures/services.yml
+++ b/pkg/provider/kubernetes/gateway/fixtures/services.yml
@@ -430,6 +430,80 @@ spec:
       name: wss
       appProtocol: kubernetes.io/wss
 
+---
+kind: EndpointSlice
+apiVersion: discovery.k8s.io/v1
+metadata:
+  name: whoami-HTTPS-abc
+  namespace: default
+  labels:
+    kubernetes.io/service-name: whoami-HTTPS
+
+addressType: IPv4
+ports:
+  - name: websecure
+    port: 8443
+endpoints:
+  - addresses:
+      - 10.10.0.16
+    conditions:
+      ready: true
+
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: whoami-HTTPS
+  namespace: default
+
+spec:
+  ports:
+    - name: websecure
+      protocol: TCP
+      appProtocol: HTTPS
+      port: 443
+      targetPort: websecure
+  selector:
+    app: containous
+    task: whoami-HTTPS
+
+---
+kind: EndpointSlice
+apiVersion: discovery.k8s.io/v1
+metadata:
+  name: whoami-HTTP-abc
+  namespace: default
+  labels:
+    kubernetes.io/service-name: whoami-HTTP
+
+addressType: IPv4
+ports:
+  - name: web
+    port: 8080
+endpoints:
+  - addresses:
+      - 10.10.0.17
+    conditions:
+      ready: true
+
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: whoami-HTTP
+  namespace: default
+
+spec:
+  ports:
+    - name: web
+      protocol: TCP
+      port: 80
+      appProtocol: HTTP
+      targetPort: web
+  selector:
+    app: containous
+    task: whoami-HTTP
+
 ---
 apiVersion: v1
 kind: Service
diff --git a/pkg/provider/kubernetes/gateway/grpcroute.go b/pkg/provider/kubernetes/gateway/grpcroute.go
index ecf208568..39b84181a 100644
--- a/pkg/provider/kubernetes/gateway/grpcroute.go
+++ b/pkg/provider/kubernetes/gateway/grpcroute.go
@@ -430,7 +430,7 @@ func getGRPCServiceProtocol(portSpec corev1.ServicePort) (string, error) {
 		return schemeH2C, nil
 	}
 
-	switch ap := *portSpec.AppProtocol; ap {
+	switch ap := strings.ToLower(*portSpec.AppProtocol); ap {
 	case appProtocolH2C:
 		return schemeH2C, nil
 	case appProtocolHTTPS:
diff --git a/pkg/provider/kubernetes/gateway/httproute.go b/pkg/provider/kubernetes/gateway/httproute.go
index 8af4cadd4..ebee5fd1f 100644
--- a/pkg/provider/kubernetes/gateway/httproute.go
+++ b/pkg/provider/kubernetes/gateway/httproute.go
@@ -817,7 +817,7 @@ func getHTTPServiceProtocol(portSpec corev1.ServicePort) (string, error) {
 		return protocol, nil
 	}
 
-	switch ap := *portSpec.AppProtocol; ap {
+	switch ap := strings.ToLower(*portSpec.AppProtocol); ap {
 	case appProtocolH2C:
 		return schemeH2C, nil
 	case appProtocolHTTP, appProtocolWS:
diff --git a/pkg/provider/kubernetes/gateway/kubernetes_test.go b/pkg/provider/kubernetes/gateway/kubernetes_test.go
index f16051051..90e93f64f 100644
--- a/pkg/provider/kubernetes/gateway/kubernetes_test.go
+++ b/pkg/provider/kubernetes/gateway/kubernetes_test.go
@@ -2959,6 +2959,14 @@ func TestLoadHTTPRoutes_backendExtensionRef(t *testing.T) {
 										Name:   "default-whoami-wss-http-80",
 										Weight: ptr.To(1),
 									},
+									{
+										Name:   "default-whoami-HTTP-http-80",
+										Weight: ptr.To(1),
+									},
+									{
+										Name:   "default-whoami-HTTPS-http-443",
+										Weight: ptr.To(1),
+									},
 								},
 							},
 						},
@@ -3004,6 +3012,34 @@ func TestLoadHTTPRoutes_backendExtensionRef(t *testing.T) {
 								},
 							},
 						},
+						"default-whoami-HTTPS-http-443": {
+							LoadBalancer: &dynamic.ServersLoadBalancer{
+								Strategy: dynamic.BalancerStrategyWRR,
+								Servers: []dynamic.Server{
+									{
+										URL: "https://10.10.0.16:8443",
+									},
+								},
+								PassHostHeader: ptr.To(true),
+								ResponseForwarding: &dynamic.ResponseForwarding{
+									FlushInterval: ptypes.Duration(100 * time.Millisecond),
+								},
+							},
+						},
+						"default-whoami-HTTP-http-80": {
+							LoadBalancer: &dynamic.ServersLoadBalancer{
+								Strategy: dynamic.BalancerStrategyWRR,
+								Servers: []dynamic.Server{
+									{
+										URL: "http://10.10.0.17:8080",
+									},
+								},
+								PassHostHeader: ptr.To(true),
+								ResponseForwarding: &dynamic.ResponseForwarding{
+									FlushInterval: ptypes.Duration(100 * time.Millisecond),
+								},
+							},
+						},
 					},
 					ServersTransports: map[string]*dynamic.ServersTransport{},
 				},