diff --git a/src/os.cc b/src/os.cc
index 70a4a04c4d3d..2ba9bc8ae1b6 100644
--- a/src/os.cc
+++ b/src/os.cc
@@ -188,6 +188,8 @@ int buffered_file::descriptor() const {
 #    undef fileno
 #  endif
   int fd = FMT_POSIX_CALL(fileno(file_));
+#elif defined(_WIN32)
+  int fd = _fileno(file_);
 #else
   int fd = fileno(file_);
 #endif