diff --git a/internal/services/appservice/linux_function_app_slot_resource.go b/internal/services/appservice/linux_function_app_slot_resource.go
index 3dd686a2de4a..492d253b4ced 100644
--- a/internal/services/appservice/linux_function_app_slot_resource.go
+++ b/internal/services/appservice/linux_function_app_slot_resource.go
@@ -344,7 +344,7 @@ func (r LinuxFunctionAppSlotResource) Create() sdk.ResourceFunc {
 			}
 
 			availabilityRequest := web.ResourceNameAvailabilityRequest{
-				Name: utils.String(functionAppSlot.Name),
+				Name: utils.String(fmt.Sprintf("%s-%s", id.SiteName, id.SlotName)),
 				Type: web.CheckNameResourceTypesMicrosoftWebsites,
 			}
 
diff --git a/internal/services/appservice/windows_function_app_slot_resource.go b/internal/services/appservice/windows_function_app_slot_resource.go
index 5900a8acc2c4..ba5fe02e5a93 100644
--- a/internal/services/appservice/windows_function_app_slot_resource.go
+++ b/internal/services/appservice/windows_function_app_slot_resource.go
@@ -350,7 +350,7 @@ func (r WindowsFunctionAppSlotResource) Create() sdk.ResourceFunc {
 			}
 
 			availabilityRequest := web.ResourceNameAvailabilityRequest{
-				Name: utils.String(functionAppSlot.Name),
+				Name: utils.String(fmt.Sprintf("%s-%s", id.SiteName, id.SlotName)),
 				Type: web.CheckNameResourceTypesMicrosoftWebsites,
 			}