diff --git a/src/w_wad.h b/src/w_wad.h
index 5872ae50a..84aafa3a4 100644
--- a/src/w_wad.h
+++ b/src/w_wad.h
@@ -180,7 +180,6 @@ UINT16 W_CheckNumForMarkerStartPwad(const char *name, UINT16 wad, UINT16 startlu
 UINT16 W_CheckNumForFullNamePK3(const char *name, UINT16 wad, UINT16 startlump);
 UINT16 W_CheckNumForFolderStartPK3(const char *name, UINT16 wad, UINT16 startlump);
 UINT16 W_CheckNumForFolderEndPK3(const char *name, UINT16 wad, UINT16 startlump);
-INT32 W_IsFolderEmpty(const char *name, UINT16 wad);
 char *W_GetLumpFolderPathPK3(UINT16 wad, UINT16 lump);
 char *W_GetLumpFolderNamePK3(UINT16 wad, UINT16 lump);