diff --git a/src/core/tcp_out.c b/src/core/tcp_out.c
index fccf06fb..a2860c6c 100644
--- a/src/core/tcp_out.c
+++ b/src/core/tcp_out.c
@@ -461,7 +461,7 @@ tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t apiflags)
      */
 #if TCP_OVERSIZE
 #if TCP_OVERSIZE_DBGCHECK
-    /* check that pcb->unsent_oversize matches last_unsent->unsent_oversize */
+    /* check that pcb->unsent_oversize matches last_unsent->oversize_left */
     LWIP_ASSERT("unsent_oversize mismatch (pcb vs. last_unsent)",
                 pcb->unsent_oversize == last_unsent->oversize_left);
 #endif /* TCP_OVERSIZE_DBGCHECK */
diff --git a/src/include/lwip/priv/tcp_priv.h b/src/include/lwip/priv/tcp_priv.h
index f68a856a..03ebcb63 100644
--- a/src/include/lwip/priv/tcp_priv.h
+++ b/src/include/lwip/priv/tcp_priv.h
@@ -249,7 +249,7 @@ struct tcp_seg {
 #if TCP_OVERSIZE_DBGCHECK
   u16_t oversize_left;     /* Extra bytes available at the end of the last
                               pbuf in unsent (used for asserting vs.
-                              tcp_pcb.unsent_oversized only) */
+                              tcp_pcb.unsent_oversize only) */
 #endif /* TCP_OVERSIZE_DBGCHECK */
 #if TCP_CHECKSUM_ON_COPY
   u16_t chksum;