diff --git a/.secrets.baseline b/.secrets.baseline
index 0197e0a1f3d..74979b4f91b 100644
--- a/.secrets.baseline
+++ b/.secrets.baseline
@@ -1156,7 +1156,7 @@
         "filename": "infra/feast-operator/internal/controller/services/services.go",
         "hashed_secret": "36dc326eb15c7bdd8d91a6b87905bcea20b637d1",
         "is_verified": false,
-        "line_number": 179
+        "line_number": 180
       }
     ],
     "infra/feast-operator/internal/controller/services/tls_test.go": [
@@ -1539,5 +1539,5 @@
       }
     ]
   },
-  "generated_at": "2026-05-20T07:55:48Z"
+  "generated_at": "2026-05-22T11:36:48Z"
 }
diff --git a/infra/feast-operator/internal/controller/services/services.go b/infra/feast-operator/internal/controller/services/services.go
index 47226d460aa..4acb8504d4e 100644
--- a/infra/feast-operator/internal/controller/services/services.go
+++ b/infra/feast-operator/internal/controller/services/services.go
@@ -32,6 +32,7 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/intstr"
+	"k8s.io/utils/ptr"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
 	"sigs.k8s.io/controller-runtime/pkg/log"
@@ -768,6 +769,17 @@ func (feast *FeastServices) setInitContainer(podSpec *corev1.PodSpec, fsYamlB64
 	}
 }
 
+// getServiceAppProtocol returns the appProtocol for a Service port.
+// The registry gRPC service uses the gRPC protocol, which requires HTTP/2.
+// Setting appProtocol allows service meshes (e.g. Istio) and load balancers
+// to correctly classify the traffic and avoid downgrading to HTTP/1.1.
+func (feast *FeastServices) getServiceAppProtocol(feastType FeastServiceType, isRestService bool) *string {
+	if feastType == RegistryFeastType && !isRestService && feast.isRegistryGrpcEnabled() {
+		return ptr.To("grpc")
+	}
+	return nil
+}
+
 func (feast *FeastServices) setService(svc *corev1.Service, feastType FeastServiceType, isRestService bool) error {
 	svc.Labels = feast.getFeastTypeLabels(feastType)
 	if feast.isOpenShiftTls(feastType) {
@@ -829,10 +841,11 @@ func (feast *FeastServices) setService(svc *corev1.Service, feastType FeastServi
 		Type:     corev1.ServiceTypeClusterIP,
 		Ports: []corev1.ServicePort{
 			{
-				Name:       scheme,
-				Port:       port,
-				Protocol:   corev1.ProtocolTCP,
-				TargetPort: intstr.FromInt(int(targetPort)),
+				Name:        scheme,
+				Port:        port,
+				Protocol:    corev1.ProtocolTCP,
+				TargetPort:  intstr.FromInt(int(targetPort)),
+				AppProtocol: feast.getServiceAppProtocol(feastType, isRestService),
 			},
 		},
 	}
diff --git a/infra/feast-operator/internal/controller/services/services_test.go b/infra/feast-operator/internal/controller/services/services_test.go
index 4b7b4343216..7cabc1d596d 100644
--- a/infra/feast-operator/internal/controller/services/services_test.go
+++ b/infra/feast-operator/internal/controller/services/services_test.go
@@ -632,6 +632,118 @@ var _ = Describe("Registry Service", func() {
 	})
 })
 
+var _ = Describe("Service AppProtocol Configuration", func() {
+	var (
+		featureStore *feastdevv1.FeatureStore
+		feast        *FeastServices
+		ctx          context.Context
+	)
+
+	BeforeEach(func() {
+		ctx = context.Background()
+		featureStore = &feastdevv1.FeatureStore{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "testfeaturestore-approtocol",
+				Namespace: "default",
+			},
+			Spec: feastdevv1.FeatureStoreSpec{
+				FeastProject: "testproject",
+				Services: &feastdevv1.FeatureStoreServices{
+					Registry: &feastdevv1.Registry{
+						Local: &feastdevv1.LocalRegistryConfig{
+							Server: &feastdevv1.RegistryServerConfigs{
+								ServerConfigs: feastdevv1.ServerConfigs{
+									ContainerConfigs: feastdevv1.ContainerConfigs{
+										DefaultCtrConfigs: feastdevv1.DefaultCtrConfigs{
+											Image: ptr.To("test-image"),
+										},
+									},
+								},
+								GRPC:    ptr.To(true),
+								RestAPI: ptr.To(false),
+							},
+						},
+					},
+				},
+			},
+		}
+		Expect(k8sClient.Create(ctx, featureStore)).To(Succeed())
+		applySpecToStatus(featureStore)
+		feast = &FeastServices{
+			Handler: handler.FeastHandler{
+				Client:       k8sClient,
+				Context:      ctx,
+				Scheme:       k8sClient.Scheme(),
+				FeatureStore: featureStore,
+			},
+		}
+		Expect(feast.ApplyDefaults()).To(Succeed())
+		applySpecToStatus(featureStore)
+	})
+
+	AfterEach(func() {
+		Expect(k8sClient.Delete(ctx, featureStore)).To(Succeed())
+	})
+
+	It("should return grpc appProtocol for the registry gRPC service", func() {
+		Expect(feast.isRegistryGrpcEnabled()).To(BeTrue())
+		Expect(feast.getServiceAppProtocol(RegistryFeastType, false)).To(Equal(ptr.To("grpc")))
+	})
+
+	It("should return nil appProtocol for the registry REST service", func() {
+		featureStore.Spec.Services.Registry.Local.Server.RestAPI = ptr.To(true)
+		Expect(k8sClient.Update(ctx, featureStore)).To(Succeed())
+		Expect(feast.ApplyDefaults()).To(Succeed())
+		applySpecToStatus(featureStore)
+
+		Expect(feast.getServiceAppProtocol(RegistryFeastType, true)).To(BeNil())
+	})
+
+	It("should return nil appProtocol for the online store service", func() {
+		Expect(feast.getServiceAppProtocol(OnlineFeastType, false)).To(BeNil())
+	})
+
+	It("should return nil appProtocol for the offline store service", func() {
+		Expect(feast.getServiceAppProtocol(OfflineFeastType, false)).To(BeNil())
+	})
+
+	It("should return nil appProtocol when registry gRPC is disabled", func() {
+		featureStore.Spec.Services.Registry.Local.Server.GRPC = ptr.To(false)
+		featureStore.Spec.Services.Registry.Local.Server.RestAPI = ptr.To(true)
+		Expect(k8sClient.Update(ctx, featureStore)).To(Succeed())
+		Expect(feast.ApplyDefaults()).To(Succeed())
+		applySpecToStatus(featureStore)
+
+		Expect(feast.isRegistryGrpcEnabled()).To(BeFalse())
+		Expect(feast.getServiceAppProtocol(RegistryFeastType, false)).To(BeNil())
+	})
+
+	It("should set grpc appProtocol on the registry gRPC Service port", func() {
+		Expect(feast.deployFeastServiceByType(RegistryFeastType)).To(Succeed())
+		svc := feast.initFeastSvc(RegistryFeastType)
+		Expect(svc).NotTo(BeNil())
+		Expect(feast.setService(svc, RegistryFeastType, false)).To(Succeed())
+
+		Expect(svc.Spec.Ports).To(HaveLen(1))
+		Expect(svc.Spec.Ports[0].AppProtocol).To(Equal(ptr.To("grpc")))
+	})
+
+	It("should not set appProtocol on the registry REST Service port", func() {
+		featureStore.Spec.Services.Registry.Local.Server.RestAPI = ptr.To(true)
+		Expect(k8sClient.Update(ctx, featureStore)).To(Succeed())
+		Expect(feast.ApplyDefaults()).To(Succeed())
+		applySpecToStatus(featureStore)
+
+		Expect(feast.deployFeastServiceByType(RegistryFeastType)).To(Succeed())
+		restSvc := feast.initFeastRestSvc(RegistryFeastType)
+		Expect(restSvc).NotTo(BeNil())
+		Expect(feast.setService(restSvc, RegistryFeastType, true)).To(Succeed())
+
+		Expect(restSvc.Spec.Ports).To(HaveLen(1))
+		Expect(restSvc.Spec.Ports[0].AppProtocol).To(BeNil())
+	})
+})
+
 var _ = Describe("Pod Container Failure Messages", func() {
 	It("should detect init container in CrashLoopBackOff", func() {
 		pod := &corev1.Pod{