diff --git a/src/api/api_msg.c b/src/api/api_msg.c
index e3361923..4e11684f 100644
--- a/src/api/api_msg.c
+++ b/src/api/api_msg.c
@@ -1182,7 +1182,7 @@ do_writemore(struct netconn *conn)
   if (dontblock && (err == ERR_MEM)) {
     /* nonblocking write failed */
     write_finished = 1;
-    err = ERR_WOULBLOCK;
+    err = ERR_WOULDBLOCK;
     /* let poll_tcp check writable space to mark the pcb
        writable again */
     conn->flags |= NETCONN_FLAG_CHECK_WRITESPACE;
diff --git a/src/api/sockets.c b/src/api/sockets.c
index 24b5f29d..21e0d1bc 100644
--- a/src/api/sockets.c
+++ b/src/api/sockets.c
@@ -135,7 +135,7 @@ static const int err_to_errno_table[] = {
   EHOSTUNREACH,  /* ERR_RTE        -4      Routing problem.         */
   EINPROGRESS,   /* ERR_INPROGRESS -5      Operation in progress    */
   EINVAL,        /* ERR_VAL        -6      Illegal value.           */
-  EWOULDBLOCK,   /* ERR_WOULBLOCK  -7      Operation would block.   */
+  EWOULDBLOCK,   /* ERR_WOULDBLOCK -7      Operation would block.   */
   ECONNABORTED,  /* ERR_ABRT       -8      Connection aborted.      */
   ECONNRESET,    /* ERR_RST        -9      Connection reset.        */
   ESHUTDOWN,     /* ERR_CLSD       -10     Connection closed.       */
diff --git a/src/include/lwip/err.h b/src/include/lwip/err.h
index b4fe0502..b35ae75f 100644
--- a/src/include/lwip/err.h
+++ b/src/include/lwip/err.h
@@ -56,7 +56,7 @@ typedef s8_t err_t;
 #define ERR_RTE        -4    /* Routing problem.         */
 #define ERR_INPROGRESS -5    /* Operation in progress    */
 #define ERR_VAL        -6    /* Illegal value.           */
-#define ERR_WOULBLOCK  -7    /* Operation would block.   */
+#define ERR_WOULDBLOCK -7    /* Operation would block.   */
 
 #define ERR_IS_FATAL(e) ((e) < ERR_VAL)