diff --git a/src/osd/sdl/sdldir.cpp b/src/osd/sdl/sdldir.cpp
index 5ec1b2fca32..251210ba400 100644
--- a/src/osd/sdl/sdldir.cpp
+++ b/src/osd/sdl/sdldir.cpp
@@ -9,7 +9,7 @@
 //============================================================
 
 #ifdef SDLMAME_WIN32
-#include "../windows/windir.c"
+#include "../windows/windir.cpp"
 #else
 
 #ifndef _LARGEFILE64_SOURCE
diff --git a/src/osd/sdl/sdlfile.cpp b/src/osd/sdl/sdlfile.cpp
index 7e3226d497a..a0a49801a95 100644
--- a/src/osd/sdl/sdlfile.cpp
+++ b/src/osd/sdl/sdlfile.cpp
@@ -9,8 +9,8 @@
 //============================================================
 
 #ifdef SDLMAME_WIN32
-#include "../windows/winfile.c"
-#include "../windows/winutil.c"
+#include "../windows/winfile.cpp"
+#include "../windows/winutil.cpp"
 #else
 
 #ifndef _LARGEFILE64_SOURCE
diff --git a/src/osd/sdl/sdlptty_win32.cpp b/src/osd/sdl/sdlptty_win32.cpp
index e9944a75c5a..fca49a12a99 100644
--- a/src/osd/sdl/sdlptty_win32.cpp
+++ b/src/osd/sdl/sdlptty_win32.cpp
@@ -9,4 +9,4 @@
 //
 //============================================================
 
-#include "../windows/winptty.c"
+#include "../windows/winptty.cpp"
diff --git a/src/osd/sdl/sdlsocket.cpp b/src/osd/sdl/sdlsocket.cpp
index efc06d17a7f..549729bf3e2 100644
--- a/src/osd/sdl/sdlsocket.cpp
+++ b/src/osd/sdl/sdlsocket.cpp
@@ -9,7 +9,7 @@
 //============================================================
 
 #ifdef SDLMAME_WIN32
-#include "../windows/winsocket.c"
+#include "../windows/winsocket.cpp"
 #else
 
 #include <stdio.h>