diff --git a/src/core/mem.c b/src/core/mem.c
index 070d103a..a3003758 100644
--- a/src/core/mem.c
+++ b/src/core/mem.c
@@ -54,13 +54,14 @@
  */
 
 #include "lwip/opt.h"
-#include "lwip/def.h"
 #include "lwip/mem.h"
+#include "lwip/def.h"
 #include "lwip/sys.h"
 #include "lwip/stats.h"
 #include "lwip/err.h"
 
 #include <string.h>
+#include <stdlib.h>
 
 #if MEM_LIBC_MALLOC || MEM_USE_POOLS
 /** mem_init is not used when using pools instead of a heap or using
diff --git a/src/include/lwip/mem.h b/src/include/lwip/mem.h
index 67aa4c6a..e4f6a64d 100644
--- a/src/include/lwip/mem.h
+++ b/src/include/lwip/mem.h
@@ -45,7 +45,6 @@ extern "C" {
 
 #if MEM_LIBC_MALLOC
 
-#include <stdlib.h>
 #include <stddef.h> /* for size_t */
 typedef size_t mem_size_t;
 #define MEM_SIZE_F SZT_F