diff --git a/vncviewer/CMakeLists.txt b/vncviewer/CMakeLists.txt
index ec89963..8be757e 100644
--- a/vncviewer/CMakeLists.txt
+++ b/vncviewer/CMakeLists.txt
@@ -29,7 +29,11 @@
   set(VNCVIEWER_SOURCES ${VNCVIEWER_SOURCES} X11PixelBuffer.cxx)
 endif()
 
-add_executable(vncviewer ${VNCVIEWER_SOURCES})
+if(WIN32)
+  add_executable(vncviewer WIN32 ${VNCVIEWER_SOURCES})
+else()
+  add_executable(vncviewer ${VNCVIEWER_SOURCES})
+endif()
 
 target_link_libraries(vncviewer rfb network rdr os Xregion ${FLTK_LIBRARIES} ${GETTEXT_LIBRARIES})