diff --git a/src/core/tcp_out.c b/src/core/tcp_out.c
index 4d39826c..fccf06fb 100644
--- a/src/core/tcp_out.c
+++ b/src/core/tcp_out.c
@@ -475,7 +475,7 @@ tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t apiflags)
       space -= oversize_used;
     }
     /* now we are either finished or oversize is zero */
-    LWIP_ASSERT("inconsistend oversize vs. len", (oversize == 0) || (pos == len));
+    LWIP_ASSERT("inconsistent oversize vs. len", (oversize == 0) || (pos == len));
 #endif /* TCP_OVERSIZE */
 
     /*