diff --git a/src/include/lwip/udp.h b/src/include/lwip/udp.h
index 09144e2e..6d674569 100644
--- a/src/include/lwip/udp.h
+++ b/src/include/lwip/udp.h
@@ -88,7 +88,7 @@ err_t            udp_send       (struct udp_pcb *pcb, struct pbuf *p);
 #define          udp_setflags(pcb, f)  ((pcb)->flags = (f))
 
 
-/* The following functions is the lower layer interface to UDP. */
+/* The following functions are the lower layer interface to UDP. */
 u8_t             udp_lookup     (struct ip_hdr *iphdr, struct netif *inp);
 void             udp_input      (struct pbuf *p, struct netif *inp);
 void             udp_init       (void);