diff --git a/pkg/apis/networking/validation/validation.go b/pkg/apis/networking/validation/validation.go
index eb08bf23c86..d0ec25726c4 100644
--- a/pkg/apis/networking/validation/validation.go
+++ b/pkg/apis/networking/validation/validation.go
@@ -599,27 +599,24 @@ func validateIngressClassParametersReference(params *networking.IngressClassPara
 		return allErrs
 	}
 
-	if params.Scope != nil || params.Namespace != nil {
-		scope := utilpointer.StringDeref(params.Scope, "")
+	scope := utilpointer.StringDeref(params.Scope, "")
 
-		if !supportedIngressClassParametersReferenceScopes.Has(scope) {
-			allErrs = append(allErrs, field.NotSupported(fldPath.Child("scope"), scope,
-				supportedIngressClassParametersReferenceScopes.List()))
-		} else {
-
-			if scope == networking.IngressClassParametersReferenceScopeNamespace {
-				if params.Namespace == nil {
-					allErrs = append(allErrs, field.Required(fldPath.Child("namespace"), "`parameters.scope` is set to 'Namespace'"))
-				} else {
-					for _, msg := range apivalidation.ValidateNamespaceName(*params.Namespace, false) {
-						allErrs = append(allErrs, field.Invalid(fldPath.Child("namespace"), *params.Namespace, msg))
-					}
+	if !supportedIngressClassParametersReferenceScopes.Has(scope) {
+		allErrs = append(allErrs, field.NotSupported(fldPath.Child("scope"), scope,
+			supportedIngressClassParametersReferenceScopes.List()))
+	} else {
+		if scope == networking.IngressClassParametersReferenceScopeNamespace {
+			if params.Namespace == nil {
+				allErrs = append(allErrs, field.Required(fldPath.Child("namespace"), "`parameters.scope` is set to 'Namespace'"))
+			} else {
+				for _, msg := range apivalidation.ValidateNamespaceName(*params.Namespace, false) {
+					allErrs = append(allErrs, field.Invalid(fldPath.Child("namespace"), *params.Namespace, msg))
 				}
 			}
+		}
 
-			if scope == networking.IngressClassParametersReferenceScopeCluster && params.Namespace != nil {
-				allErrs = append(allErrs, field.Forbidden(fldPath.Child("namespace"), "`parameters.scope` is set to 'Cluster'"))
-			}
+		if scope == networking.IngressClassParametersReferenceScopeCluster && params.Namespace != nil {
+			allErrs = append(allErrs, field.Forbidden(fldPath.Child("namespace"), "`parameters.scope` is set to 'Cluster'"))
 		}
 	}
 
diff --git a/pkg/apis/networking/validation/validation_test.go b/pkg/apis/networking/validation/validation_test.go
index 65f1a494aff..04d110b35bf 100644
--- a/pkg/apis/networking/validation/validation_test.go
+++ b/pkg/apis/networking/validation/validation_test.go
@@ -1652,6 +1652,14 @@ func TestValidateIngressClass(t *testing.T) {
 			),
 			expectedErrs: field.ErrorList{},
 		},
+		"valid name, valid controller, invalid scope": {
+			ingressClass: makeValidIngressClass("test123", "foo.co/bar",
+				setParams(makeIngressClassParams(nil, "foo", "bar", nil, utilpointer.String("foo_ns"))),
+			),
+			expectedErrs: field.ErrorList{
+				field.Required(field.NewPath("spec.parameters.scope"), ""),
+			},
+		},
 		"namespace not set when scope is Namespace": {
 			ingressClass: makeValidIngressClass("test123", "foo.co/bar",
 				setParams(makeIngressClassParams(nil, "foo", "bar", utilpointer.String("Namespace"), nil)),