diff --git a/fmt/format.cc b/fmt/format.cc
index 8fb3266a40b7..f4fc3df10c06 100644
--- a/fmt/format.cc
+++ b/fmt/format.cc
@@ -41,6 +41,9 @@
 #endif
 
 #if FMT_USE_WINDOWS_H
+# ifndef WIN32_LEAN_AND_MEAN
+#  define WIN32_LEAN_AND_MEAN
+# endif
 # if defined(NOMINMAX) || defined(FMT_WIN_MINMAX)
 #  include <windows.h>
 # else
diff --git a/fmt/posix.cc b/fmt/posix.cc
index d86578fb5f6b..356668c135ab 100644
--- a/fmt/posix.cc
+++ b/fmt/posix.cc
@@ -21,6 +21,9 @@
 #ifndef _WIN32
 # include <unistd.h>
 #else
+# ifndef WIN32_LEAN_AND_MEAN
+#  define WIN32_LEAN_AND_MEAN
+# endif
 # include <windows.h>
 # include <io.h>