diff --git a/rostests/apitests/user32/CMakeLists.txt b/rostests/apitests/user32/CMakeLists.txt
index e11fdf4558c..9fc9374db52 100644
--- a/rostests/apitests/user32/CMakeLists.txt
+++ b/rostests/apitests/user32/CMakeLists.txt
@@ -9,6 +9,7 @@ list(APPEND SOURCE
     GetSystemMetrics.c
     GetIconInfo.c
     GetPeekMessage.c
+    DeferWindowPos.c
     testlist.c
     user32_apitest.rc)
 
diff --git a/rostests/apitests/user32/DeferWindowPos.c b/rostests/apitests/user32/DeferWindowPos.c
new file mode 100644
index 00000000000..b9a3d725c33
--- /dev/null
+++ b/rostests/apitests/user32/DeferWindowPos.c
@@ -0,0 +1,170 @@
+/*
+ * PROJECT:         ReactOS API tests
+ * LICENSE:         GPL - See COPYING in the top level directory
+ * PURPOSE:         Test for DeferWindowPos function family
+ * PROGRAMMERS:     Thomas Faber
+ */
+
+#include <stdio.h>
+#include <wine/test.h>
+#include <windows.h>
+
+#define ok_windowpos(hwnd, x, y, w, h, wnd) do { RECT rt; GetWindowRect(hwnd, &rt); \
+                                                 ok(rt.left == (x) && rt.top == (y) && rt.right == (x)+(w) && rt.bottom == (y)+(h), \
+                                                    "Unexpected %s position: (%ld, %ld) - (%ld, %ld)\n", wnd, rt.left, rt.top, rt.right, rt.bottom); } while (0)
+
+#define ok_lasterr(err, s) ok(GetLastError() == (err), "%s error = %lu\n", s, GetLastError())
+
+static void Test_DeferWindowPos(HWND hWnd, HWND hWnd2)
+{
+    HDWP hDwp;
+    BOOL ret;
+
+    /* close invalid handles */
+    SetLastError(DNS_ERROR_RCODE_NXRRSET);
+    ret = EndDeferWindowPos(NULL);
+    ok(ret == 0, "EndDeferWindowPos succeeded with invalid handle\n");
+    ok_lasterr(ERROR_INVALID_DWP_HANDLE, "EndDeferWindowPos");
+
+    SetLastError(DNS_ERROR_RCODE_NXRRSET);
+    ret = EndDeferWindowPos((HDWP)-1);
+    ok(ret == 0, "EndDeferWindowPos succeeded with invalid handle\n");
+    ok_lasterr(ERROR_INVALID_DWP_HANDLE, "EndDeferWindowPos");
+    
+    /* negative window count */
+    SetLastError(DNS_ERROR_RCODE_NXRRSET);
+    hDwp = BeginDeferWindowPos(-1);
+    ok(hDwp == NULL, "BeginDeferWindowPos failed\n");
+    ok_lasterr(ERROR_INVALID_PARAMETER, "BeginDeferWindowPos");
+
+    /* zero windows */
+    SetLastError(DNS_ERROR_RCODE_NXRRSET);
+    hDwp = BeginDeferWindowPos(0);
+    ok(hDwp != NULL, "BeginDeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "BeginDeferWindowPos");
+    ret = EndDeferWindowPos(hDwp);
+    ok(ret != 0, "EndDeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "EndDeferWindowPos");
+
+    /* more windows than expected */
+    SetLastError(DNS_ERROR_RCODE_NXRRSET);
+    hDwp = BeginDeferWindowPos(0);
+    ok(hDwp != NULL, "BeginDeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "BeginDeferWindowPos");
+    hDwp = DeferWindowPos(hDwp, hWnd, NULL, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER);
+    ok(hDwp != NULL, "DeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "DeferWindowPos");
+    ret = EndDeferWindowPos(hDwp);
+    ok(ret != 0, "EndDeferWindowPos failed\n");
+    ok(GetLastError() == ERROR_SUCCESS /* win7 sp1/x64 */
+       || GetLastError() == ERROR_INVALID_WINDOW_HANDLE /* 2k3 sp1/x86 */,
+       "EndDeferWindowPos error = %lu\n", GetLastError());
+    ok_windowpos(hWnd, 10, 20, 200, 210, "Window 1");
+
+    /* more windows than expected 2 */
+    SetLastError(DNS_ERROR_RCODE_NXRRSET);
+    hDwp = BeginDeferWindowPos(1);
+    ok(hDwp != NULL, "BeginDeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "BeginDeferWindowPos");
+    hDwp = DeferWindowPos(hDwp, hWnd, NULL, 30, 20, 190, 195, SWP_NOZORDER);
+    ok(hDwp != NULL, "DeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "DeferWindowPos");
+    hDwp = DeferWindowPos(hDwp, hWnd2, NULL, 20, 30, 195, 190, SWP_NOZORDER);
+    ok(hDwp != NULL, "DeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "DeferWindowPos");
+    ret = EndDeferWindowPos(hDwp);
+    ok(ret != 0, "EndDeferWindowPos failed\n");
+    ok_lasterr(ERROR_SUCCESS, "EndDeferWindowPos");
+    ok_windowpos(hWnd, 30, 20, 190, 195, "Window 1");
+    ok_windowpos(hWnd2, 20, 30, 195, 190, "Window 2");
+
+    /* fewer windows than expected */
+    MoveWindow(hWnd, 10, 20, 200, 210, FALSE);
+    SetLastError(DNS_ERROR_RCODE_NXRRSET);
+    hDwp = BeginDeferWindowPos(2);
+    ok(hDwp != NULL, "BeginDeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "BeginDeferWindowPos");
+    hDwp = DeferWindowPos(hDwp, hWnd, NULL, 20, 10, 210, 200, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER);
+    ok(hDwp != NULL, "DeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "DeferWindowPos");
+    ret = EndDeferWindowPos(hDwp);
+    ok(ret != 0, "EndDeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "EndDeferWindowPos");
+    ok_windowpos(hWnd, 10, 20, 200, 210, "Window 1");
+
+    /* no operation, 1 window */
+    SetLastError(DNS_ERROR_RCODE_NXRRSET);
+    hDwp = BeginDeferWindowPos(1);
+    ok(hDwp != NULL, "BeginDeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "BeginDeferWindowPos");
+    hDwp = DeferWindowPos(hDwp, hWnd, NULL, 20, 10, 210, 200, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER);
+    ok(hDwp != NULL, "DeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "DeferWindowPos");
+    ret = EndDeferWindowPos(hDwp);
+    ok(ret != 0, "EndDeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "EndDeferWindowPos");
+    ok_windowpos(hWnd, 10, 20, 200, 210, "Window 1");
+
+    /* same window twice */
+    SetLastError(DNS_ERROR_RCODE_NXRRSET);
+    hDwp = BeginDeferWindowPos(2);
+    ok(hDwp != NULL, "BeginDeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "BeginDeferWindowPos");
+    hDwp = DeferWindowPos(hDwp, hWnd, NULL, 80, 90, 220, 210, SWP_NOZORDER);
+    ok(hDwp != NULL, "DeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "DeferWindowPos");
+    hDwp = DeferWindowPos(hDwp, hWnd, NULL, 100, 110, 230, 250, SWP_NOZORDER);
+    ok(hDwp != NULL, "DeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "DeferWindowPos");
+    ret = EndDeferWindowPos(hDwp);
+    ok(ret != 0, "EndDeferWindowPos failed\n");
+    ok_lasterr(ERROR_SUCCESS, "EndDeferWindowPos");
+    ok_windowpos(hWnd, 100, 110, 230, 250, "Window 1");
+
+    /* move & resize operation, 1 window */
+    SetLastError(DNS_ERROR_RCODE_NXRRSET);
+    hDwp = BeginDeferWindowPos(1);
+    ok(hDwp != NULL, "BeginDeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "BeginDeferWindowPos");
+    hDwp = DeferWindowPos(hDwp, hWnd, NULL, 20, 10, 210, 200, SWP_NOZORDER);
+    ok(hDwp != NULL, "DeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "DeferWindowPos");
+    ret = EndDeferWindowPos(hDwp);
+    ok(ret != 0, "EndDeferWindowPos failed\n");
+    ok_lasterr(ERROR_SUCCESS, "EndDeferWindowPos");
+    ok_windowpos(hWnd, 20, 10, 210, 200, "Window 1");
+
+    /* move & resize operation, 2 windows */
+    SetLastError(DNS_ERROR_RCODE_NXRRSET);
+    hDwp = BeginDeferWindowPos(2);
+    ok(hDwp != NULL, "BeginDeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "BeginDeferWindowPos");
+    hDwp = DeferWindowPos(hDwp, hWnd, NULL, 50, 60, 230, 240, SWP_NOZORDER);
+    ok(hDwp != NULL, "DeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "DeferWindowPos");
+    hDwp = DeferWindowPos(hDwp, hWnd2, NULL, 70, 80, 250, 260, SWP_NOZORDER);
+    ok(hDwp != NULL, "DeferWindowPos failed\n");
+    ok_lasterr(DNS_ERROR_RCODE_NXRRSET, "DeferWindowPos");
+    ret = EndDeferWindowPos(hDwp);
+    ok(ret != 0, "EndDeferWindowPos failed\n");
+    ok_lasterr(ERROR_SUCCESS, "EndDeferWindowPos");
+    ok_windowpos(hWnd, 50, 60, 230, 240, "Window 1");
+    ok_windowpos(hWnd2, 70, 80, 250, 260, "Window 2");
+}
+
+START_TEST(DeferWindowPos)
+{
+    HWND hWnd = CreateWindowExW(0, L"EDIT", L"abc", 0, 10, 20,
+        200, 210, NULL, NULL, GetModuleHandle(NULL), NULL);
+    HWND hWnd2 = CreateWindowExW(0, L"EDIT", L"def", 0, 30, 40,
+        220, 230, NULL, NULL, GetModuleHandle(NULL), NULL);
+    ok(hWnd != NULL, "CreateWindow failed\n");
+    ok(hWnd2 != NULL, "CreateWindow failed\n");
+    ok_windowpos(hWnd, 10, 20, 200, 210, "Window 1");
+    ok_windowpos(hWnd2, 30, 40, 220, 230, "Window 2");
+
+    Test_DeferWindowPos(hWnd, hWnd2);
+    
+    DestroyWindow(hWnd2);
+    DestroyWindow(hWnd);
+}
diff --git a/rostests/apitests/user32/testlist.c b/rostests/apitests/user32/testlist.c
index b37d7ca0607..f89be66ed15 100644
--- a/rostests/apitests/user32/testlist.c
+++ b/rostests/apitests/user32/testlist.c
@@ -12,6 +12,7 @@ extern void func_ScrollWindowEx(void);
 extern void func_GetSystemMetrics(void);
 extern void func_GetIconInfo(void);
 extern void func_GetPeekMessage(void);
+extern void func_DeferWindowPos(void);
 
 const struct test winetest_testlist[] =
 {
@@ -22,6 +23,7 @@ const struct test winetest_testlist[] =
     { "GetSystemMetrics", func_GetSystemMetrics },
     { "GetIconInfo", func_GetIconInfo },
     { "GetPeekMessage", func_GetPeekMessage },
+    { "DeferWindowPos", func_DeferWindowPos },
 
     { 0, 0 }
 };
diff --git a/rostests/apitests/user32/user32_apitest.rbuild b/rostests/apitests/user32/user32_apitest.rbuild
index 8aaa1dfb4ee..6f5489c31d2 100644
--- a/rostests/apitests/user32/user32_apitest.rbuild
+++ b/rostests/apitests/user32/user32_apitest.rbuild
@@ -17,6 +17,7 @@
 	<file>GetSystemMetrics.c</file>
 	<file>GetIconInfo.c</file>
 	<file>GetPeekMessage.c</file>
+	<file>DeferWindowPos.c</file>
 
 </module>
 </group>