diff --git a/lib/open3.rb b/lib/open3.rb
index 9e435f83f8..247239e262 100644
--- a/lib/open3.rb
+++ b/lib/open3.rb
@@ -223,7 +223,7 @@ module Open3
   #   stdout_str, stderr_str, status = Open3.capture3([env,] cmd... [, opts])
   #
   # The arguments env, cmd and opts are passed to Open3.popen3 except
-  # opts[:stdin_data] and opts[:stdin_data].  See Process.spawn.
+  # opts[:stdin_data].  See Process.spawn.
   #
   # If opts[:stdin_data] is specified, it is sent to the command's standard input.
   #
@@ -287,7 +287,7 @@ module Open3
   #   stdout_str, status = Open3.capture2([env,] cmd... [, opts])
   #
   # The arguments env, cmd and opts are passed to Open3.popen3 except
-  # opts[:stdin_data] and opts[:stdin_data].  See Process.spawn.
+  # opts[:stdin_data].  See Process.spawn.
   #
   # If opts[:stdin_data] is specified, it is sent to the command's standard input.
   #
@@ -339,7 +339,7 @@ module Open3
   #   stdout_and_stderr_str, status = Open3.capture2e([env,] cmd... [, opts])
   #
   # The arguments env, cmd and opts are passed to Open3.popen3 except
-  # opts[:stdin_data] and opts[:stdin_data].  See Process.spawn.
+  # opts[:stdin_data].  See Process.spawn.
   #
   # If opts[:stdin_data] is specified, it is sent to the command's standard input.
   #