diff --git a/core/sys/windows/shell32.odin b/core/sys/windows/shell32.odin
index 1a0844b39..0fdcc69d7 100644
--- a/core/sys/windows/shell32.odin
+++ b/core/sys/windows/shell32.odin
@@ -38,6 +38,8 @@ foreign shell32 {
 	DragQueryPoint  :: proc(hDrop: HDROP, ppt: ^POINT) -> BOOL ---
 	DragQueryFileW  :: proc(hDrop: HDROP, iFile: UINT, lpszFile: LPWSTR, cch: UINT) -> UINT ---
 	DragFinish      :: proc(hDrop: HDROP) --- // @New
+
+	AssocCreateForClasses :: proc (rgClasses: [^]ASSOCIATIONELEMENT, cClasses: ULONG, riid: REFIID, ppv: ^rawptr) -> HRESULT ---
 }
 
 APPBARDATA :: struct {
diff --git a/core/sys/windows/types.odin b/core/sys/windows/types.odin
index f9485c48c..bb0291e2a 100644
--- a/core/sys/windows/types.odin
+++ b/core/sys/windows/types.odin
@@ -5392,3 +5392,24 @@ FILETYPEATTRIBUTEFLAGS_Bits :: enum DWORD {
 	AlwaysUseDirectInvoke = 22,
 }
 FILETYPEATTRIBUTEFLAGS :: bit_set[FILETYPEATTRIBUTEFLAGS_Bits; DWORD]
+
+ASSOCCLASS :: enum c_int {
+	SHELL_KEY = 0,
+	PROGID_KEY,
+	PROGID_STR,
+	CLSID_KEY,
+	CLSID_STR,
+	APP_KEY,
+	APP_STR,
+	SYSTEM_STR,
+	FOLDER,
+	STAR,
+	FIXED_PROGID_STR,
+	PROTOCOL_STR,
+}
+
+ASSOCIATIONELEMENT :: struct {
+	ac:       ASSOCCLASS,
+	hkClass:  HKEY,
+	pszClass: PCWSTR,
+}