diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7646af756..1b5f72c2c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -219,7 +219,7 @@ if( MSVC )
 	set( DEB_C_FLAGS "/D _CRTDBG_MAP_ALLOC /MTd" )
 
 	# Disable warnings for unsecure CRT functions from VC8+
-	set( ALL_C_FLAGS "${ALL_C_FLAGS} /wd4996 /DUNICODE /D_UNICODE" )
+	set( ALL_C_FLAGS "${ALL_C_FLAGS} /wd4996 /DUNICODE /D_UNICODE /D_WIN32_WINNT=0x0600" )
 
 	# The CMake configurations set /GR and /MD by default, which conflict with our settings.
 	string(REPLACE "/MD " " " CMAKE_CXX_FLAGS_RELEASE ${CMAKE_CXX_FLAGS_RELEASE} )
diff --git a/src/d_anonstats.cpp b/src/d_anonstats.cpp
index 7378fc17a..4b0319149 100644
--- a/src/d_anonstats.cpp
+++ b/src/d_anonstats.cpp
@@ -12,7 +12,6 @@ void D_ConfirmSendStats()
 #else // !NO_SEND_STATS
 
 #if defined(_WIN32)
-#define _WIN32_WINNT 0x0501
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 #include <winsock2.h>
diff --git a/src/win32/hardware.cpp b/src/win32/hardware.cpp
index 2674d553a..98af9957c 100644
--- a/src/win32/hardware.cpp
+++ b/src/win32/hardware.cpp
@@ -32,7 +32,6 @@
 **
 */
 
-#define _WIN32_WINNT 0x0501
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 #include <mmsystem.h>
diff --git a/src/win32/helperthread.cpp b/src/win32/helperthread.cpp
index f6f74554f..f5874b99e 100644
--- a/src/win32/helperthread.cpp
+++ b/src/win32/helperthread.cpp
@@ -35,7 +35,6 @@
 **
 */
 
-#define _WIN32_WINNT	0x0400
 #include "helperthread.h"
 
 //==========================================================================
diff --git a/src/win32/i_cd.cpp b/src/win32/i_cd.cpp
index cd00fbcfc..4e1c633b3 100644
--- a/src/win32/i_cd.cpp
+++ b/src/win32/i_cd.cpp
@@ -32,7 +32,6 @@
 **
 */
 
-#define _WIN32_WINNT	0x0400
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 #include <mmsystem.h>
diff --git a/src/win32/i_crash.cpp b/src/win32/i_crash.cpp
index 52daf378d..1a2df352a 100644
--- a/src/win32/i_crash.cpp
+++ b/src/win32/i_crash.cpp
@@ -35,7 +35,6 @@
 // HEADER FILES ------------------------------------------------------------
 
 #define WIN32_LEAN_AND_MEAN
-#define _WIN32_WINNT 0x0501
 #include <windows.h>
 #include <richedit.h>
 #include <tlhelp32.h>
diff --git a/src/win32/i_dijoy.cpp b/src/win32/i_dijoy.cpp
index 471152fe8..a47b28f9d 100644
--- a/src/win32/i_dijoy.cpp
+++ b/src/win32/i_dijoy.cpp
@@ -35,7 +35,6 @@
 
 #define WIN32_LEAN_AND_MEAN
 #define DIRECTINPUT_VERSION 0x800
-#define _WIN32_WINNT 0x0501
 #include <windows.h>
 #include <dinput.h>
 #ifndef __GNUC__
diff --git a/src/win32/i_input.cpp b/src/win32/i_input.cpp
index cbfa2864b..fb6239869 100644
--- a/src/win32/i_input.cpp
+++ b/src/win32/i_input.cpp
@@ -35,11 +35,6 @@
 // DI3 only supports up to 4 mouse buttons, and I want the joystick to
 // be read using DirectInput instead of winmm.
 
-#define DIRECTINPUT_VERSION 0x800
-#if !defined(_WIN32_WINNT) || (_WIN32_WINNT < 0x0501)
-#define _WIN32_WINNT 0x0501			// Support the mouse wheel and session notification.
-#endif
-
 #define WIN32_LEAN_AND_MEAN
 #define __BYTEBOOL__
 #ifndef __GNUC__
diff --git a/src/win32/i_keyboard.cpp b/src/win32/i_keyboard.cpp
index 69571cbfd..7ab02ada0 100644
--- a/src/win32/i_keyboard.cpp
+++ b/src/win32/i_keyboard.cpp
@@ -35,7 +35,6 @@
 
 #define WIN32_LEAN_AND_MEAN
 #define DIRECTINPUT_VERSION 0x800
-#define _WIN32_WINNT 0x0501
 #include <windows.h>
 #include <dinput.h>
 
diff --git a/src/win32/i_main.cpp b/src/win32/i_main.cpp
index de4b5e2c9..6d9c9f771 100644
--- a/src/win32/i_main.cpp
+++ b/src/win32/i_main.cpp
@@ -35,7 +35,6 @@
 // HEADER FILES ------------------------------------------------------------
 
 #define WIN32_LEAN_AND_MEAN
-#define _WIN32_WINNT 0x0501
 #include <windows.h>
 #include <mmsystem.h>
 #include <objbase.h>
diff --git a/src/win32/i_mouse.cpp b/src/win32/i_mouse.cpp
index 9915479b7..e786a11c7 100644
--- a/src/win32/i_mouse.cpp
+++ b/src/win32/i_mouse.cpp
@@ -35,7 +35,6 @@
 
 #define WIN32_LEAN_AND_MEAN
 #define DIRECTINPUT_VERSION 0x800
-#define _WIN32_WINNT 0x0501
 #include <windows.h>
 #include <dinput.h>
 
diff --git a/src/win32/i_rawps2.cpp b/src/win32/i_rawps2.cpp
index 2fdfe4c21..a4214e479 100644
--- a/src/win32/i_rawps2.cpp
+++ b/src/win32/i_rawps2.cpp
@@ -34,7 +34,6 @@
 // HEADER FILES ------------------------------------------------------------
 
 #define WIN32_LEAN_AND_MEAN
-#define _WIN32_WINNT 0x0501
 #include <windows.h>
 
 #include "i_input.h"
diff --git a/src/win32/i_specialpaths.cpp b/src/win32/i_specialpaths.cpp
index c354fe965..d109d077c 100644
--- a/src/win32/i_specialpaths.cpp
+++ b/src/win32/i_specialpaths.cpp
@@ -33,7 +33,6 @@
 **
 */
 
-#define _WIN32_WINNT 0x0600
 #include <windows.h>
 #include <lmcons.h>
 #include <shlobj.h>
diff --git a/src/win32/i_xinput.cpp b/src/win32/i_xinput.cpp
index 50108991a..710d2f295 100644
--- a/src/win32/i_xinput.cpp
+++ b/src/win32/i_xinput.cpp
@@ -36,7 +36,6 @@
 // HEADER FILES ------------------------------------------------------------
 
 #define WIN32_LEAN_AND_MEAN
-#define _WIN32_WINNT 0x0501
 #include <windows.h>
 #include <xinput.h>
 #include <limits.h>
diff --git a/src/win32/st_start.cpp b/src/win32/st_start.cpp
index dc6b0694d..8acb6ddbb 100644
--- a/src/win32/st_start.cpp
+++ b/src/win32/st_start.cpp
@@ -35,7 +35,6 @@
 // HEADER FILES ------------------------------------------------------------
 
 #define WIN32_LEAN_AND_MEAN
-#define _WIN32_WINNT 0x0501	// required to get the MARQUEE defines
 #include <windows.h>
 #include <commctrl.h>
 #include "resource.h"