diff --git a/azurerm/internal/services/web/resource_arm_function_app.go b/azurerm/internal/services/web/resource_arm_function_app.go
index 47870acde88c..e5d143fff1fb 100644
--- a/azurerm/internal/services/web/resource_arm_function_app.go
+++ b/azurerm/internal/services/web/resource_arm_function_app.go
@@ -448,7 +448,7 @@ func resourceArmFunctionAppUpdate(d *schema.ResourceData, meta interface{}) erro
 	kind := "functionapp"
 	if osTypeRaw, ok := d.GetOk("os_type"); ok {
 		osType := osTypeRaw.(string)
-		if osType == "Linux" {
+		if osType == "linux" {
 			kind = "functionapp,linux"
 		}
 	}