diff --git a/acinclude.m4 b/acinclude.m4
index fe0e020b0..8a6c414a7 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -199,8 +199,6 @@ AC_DEFUN([CURL_CHECK_HEADER_WINDOWS], [
     yes)
       AC_DEFINE_UNQUOTED(HAVE_WINDOWS_H, 1,
         [Define to 1 if you have the windows.h header file.])
-      AC_DEFINE_UNQUOTED(WIN32_LEAN_AND_MEAN, 1,
-        [Define to avoid automatic inclusion of winsock.h])
       ;;
   esac
 ])
diff --git a/lib/curl_config.h.cmake b/lib/curl_config.h.cmake
index 812d96977..c1452b3e7 100644
--- a/lib/curl_config.h.cmake
+++ b/lib/curl_config.h.cmake
@@ -972,9 +972,6 @@
 /* Version number of package */
 #cmakedefine VERSION ${VERSION}
 
-/* Define to avoid automatic inclusion of winsock.h */
-#cmakedefine WIN32_LEAN_AND_MEAN 1
-
 /* Define to 1 if OS is AIX. */
 #ifndef _ALL_SOURCE
 #  undef _ALL_SOURCE