diff --git a/g10/gpg.h b/g10/gpg.h
index 9b8b77ca0..1bad5515a 100644
--- a/g10/gpg.h
+++ b/g10/gpg.h
@@ -24,6 +24,10 @@
    correct value and may be of advantage if we ever have to do
    special things. */
 
+#ifdef HAVE_W32_SYSTEM
+# define WIN32_LEAN_AND_MEAN 1
+#endif
+
 #ifdef GPG_ERR_SOURCE_DEFAULT
 #error GPG_ERR_SOURCE_DEFAULT already defined
 #endif
diff --git a/g10/misc.c b/g10/misc.c
index 77c8f269c..97809692e 100644
--- a/g10/misc.c
+++ b/g10/misc.c
@@ -42,6 +42,7 @@
 #include <time.h>
 #include <process.h>
 #ifdef HAVE_WINSOCK2_H
+# define WIN32_LEAN_AND_MEAN 1
 # include <winsock2.h>
 #endif
 #include <windows.h>