diff --git a/reactos/dll/win32/shlwapi/shlwapi.spec b/reactos/dll/win32/shlwapi/shlwapi.spec
index 1a9e205e033..805e47c2dab 100644
--- a/reactos/dll/win32/shlwapi/shlwapi.spec
+++ b/reactos/dll/win32/shlwapi/shlwapi.spec
@@ -767,7 +767,7 @@
 767 stdcall StrCSpnW(wstr wstr)
 768 stdcall StrCatBuffA(str str long)
 769 stdcall StrCatBuffW(wstr wstr long)
-#770 StrCatChainW
+770 stdcall StrCatChainW (ptr long long wstr)
 771 stdcall StrCatW(ptr wstr)
 772 stdcall StrChrA(str long)
 773 stdcall StrChrIA(str long)
diff --git a/reactos/dll/win32/shlwapi/string.c b/reactos/dll/win32/shlwapi/string.c
index db7c353041d..eae52dcbea2 100644
--- a/reactos/dll/win32/shlwapi/string.c
+++ b/reactos/dll/win32/shlwapi/string.c
@@ -437,6 +437,47 @@ LPWSTR WINAPI StrCatW(LPWSTR lpszStr, LPCWSTR lpszSrc)
   return lpszStr;
 }
 
+/*************************************************************************
+ * StrCatChainW	[SHLWAPI.@]
+ *
+ * Concatenates two unicode strings.
+ *
+ * PARAMS
+ *  lpszStr [O] Initial string
+ *  cchMax  [I] Length of destination buffer
+ *  ichAt   [I] Offset from the destination buffer to begin concatenation
+ *  lpszCat [I] String to concatenate
+ *
+ * RETURNS
+ *  The offset from the beginning of pszDst to the terminating NULL.
+ */
+DWORD WINAPI StrCatChainW(LPWSTR lpszStr, DWORD cchMax, DWORD ichAt, LPCWSTR lpszCat)
+{
+  TRACE("(%s,%u,%d,%s)\n", debugstr_w(lpszStr), cchMax, ichAt, debugstr_w(lpszCat));
+
+  if (ichAt == -1)
+    ichAt = strlenW(lpszStr);
+
+  if (!cchMax)
+    return ichAt;
+
+  if (ichAt == cchMax)
+    ichAt--;
+
+  if (lpszCat && ichAt < cchMax)
+  {
+    lpszStr += ichAt;
+    while (ichAt < cchMax - 1 && *lpszCat)
+    {
+      *lpszStr++ = *lpszCat++;
+      ichAt++;
+    }
+    *lpszStr = 0;
+  }
+
+  return ichAt;
+}
+
 /*************************************************************************
  * StrCpyW	[SHLWAPI.@]
  *