diff --git a/src/core/netif.c b/src/core/netif.c
index 33560ae9..10e5a865 100644
--- a/src/core/netif.c
+++ b/src/core/netif.c
@@ -51,7 +51,6 @@
 #include "lwip/stats.h"
 #include "lwip/sys.h"
 #if ENABLE_LOOPBACK
-#include "lwip/sys.h"
 #if LWIP_NETIF_LOOPBACK_MULTITHREADING
 #include "lwip/tcpip.h"
 #endif /* LWIP_NETIF_LOOPBACK_MULTITHREADING */
diff --git a/src/netif/ppp/ppp.c b/src/netif/ppp/ppp.c
index 02b90f25..6d4f3a62 100644
--- a/src/netif/ppp/ppp.c
+++ b/src/netif/ppp/ppp.c
@@ -94,7 +94,6 @@
 #include "lwip/tcpip.h"
 #include "lwip/api.h"
 #include "lwip/snmp.h"
-#include "lwip/sys.h"
 #include "lwip/ip4.h" /* for ip4_input() */
 #if PPP_IPV6_SUPPORT
 #include "lwip/ip6.h" /* for ip6_input() */