diff --git a/src/nvim/strings.c b/src/nvim/strings.c
index 5ee29b9172..f7218cc267 100644
--- a/src/nvim/strings.c
+++ b/src/nvim/strings.c
@@ -1,4 +1,5 @@
 #include <inttypes.h>
+#include <stdarg.h>
 #include <stdbool.h>
 #include <string.h>
 #include <math.h>