diff --git a/ChangeLog b/ChangeLog
index b130e2c3ee..ed47599c7b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Jan 12 18:34:34 2016  Martin Duerst  <duerst@it.aoyama.ac.jp>
+
+	* string.c: minor grammar fix [ci skip]
+
 Mon Jan 12 16:09:09 2016  Martin Duerst  <duerst@it.aoyama.ac.jp>
 
 	* test/ruby/enc/test_casing_options.rb: Tests for option
diff --git a/string.c b/string.c
index c553ee26b9..deea8a11f7 100644
--- a/string.c
+++ b/string.c
@@ -8600,7 +8600,7 @@ rb_str_b(VALUE str)
  *  call-seq:
  *     str.valid_encoding?  -> true or false
  *
- *  Returns true for a string which encoded correctly.
+ *  Returns true for a string which is encoded correctly.
  *
  *    "\xc2\xa1".force_encoding("UTF-8").valid_encoding?  #=> true
  *    "\xc2".force_encoding("UTF-8").valid_encoding?      #=> false