diff --git a/dlls/comctl32/comctl32.spec b/dlls/comctl32/comctl32.spec
index aff8c8b8335..1e92e5fe95b 100644
--- a/dlls/comctl32/comctl32.spec
+++ b/dlls/comctl32/comctl32.spec
@@ -127,11 +127,12 @@
 @ stdcall DestroyPropertySheetPage(long)
 @ stdcall -private DllGetVersion(ptr)
 @ stdcall -private DllInstall(long wstr)
-@ stdcall DPA_GetSize(ptr)
+@ stdcall -ret64 DPA_GetSize(ptr)
 @ stdcall DrawShadowText(long wstr long ptr long long long long long)
 @ stdcall DrawStatusText(long ptr ptr long) DrawStatusTextA
 @ stdcall DrawStatusTextW(long ptr wstr long)
 @ stdcall DSA_Clone(ptr)
+@ stdcall -ret64 DSA_GetSize(ptr)
 @ stdcall FlatSB_EnableScrollBar (long long long)
 @ stdcall FlatSB_GetScrollInfo (long long ptr)
 @ stdcall FlatSB_GetScrollPos (long long)
diff --git a/dlls/comctl32/dsa.c b/dlls/comctl32/dsa.c
index 73f0d3041a2..32f9926b689 100644
--- a/dlls/comctl32/dsa.c
+++ b/dlls/comctl32/dsa.c
@@ -470,3 +470,23 @@ HDSA WINAPI DSA_Clone(HDSA hdsa)
 
     return dest;
 }
+
+/**************************************************************************
+ * DSA_GetSize [COMCTL32.@]
+ *
+ * Returns allocated memory size for this array
+ *
+ * PARAMS
+ *     hdsa [I] handle to the dynamic storage array
+ *
+ * RETURNS
+ *     Size
+ */
+ULONGLONG WINAPI DSA_GetSize(HDSA hdsa)
+{
+    TRACE("(%p)\n", hdsa);
+
+    if (!hdsa) return 0;
+
+    return sizeof(*hdsa) + hdsa->nMaxCount*hdsa->nItemSize;
+}