diff --git a/mm/iob/iob_trimhead.c b/mm/iob/iob_trimhead.c
index 30d94b6e3b..602ad68950 100644
--- a/mm/iob/iob_trimhead.c
+++ b/mm/iob/iob_trimhead.c
@@ -61,7 +61,7 @@ FAR struct iob_s *iob_trimhead(FAR struct iob_s *iob, unsigned int trimlen,
 
   if (iob && trimlen > 0)
     {
-      /* Trim from the head of the I/IO buffer chain */
+      /* Trim from the head of the I/O buffer chain */
 
       pktlen = iob->io_pktlen;
       while (trimlen > 0 && iob != NULL)