diff --git a/src/script/api/script_list.hpp b/src/script/api/script_list.hpp
index c2c235314b..c3cc0382eb 100644
--- a/src/script/api/script_list.hpp
+++ b/src/script/api/script_list.hpp
@@ -25,7 +25,7 @@ class ScriptListSorter;
 class ScriptList : public ScriptObject {
 public:
 	/** Type of sorter */
-	enum SorterType {
+	enum SorterType : uint8_t {
 		SORT_BY_VALUE, ///< Sort the list based on the value of the item.
 		SORT_BY_ITEM,  ///< Sort the list based on the item itself.
 	};