diff --git a/lib/thor/actions.rb b/lib/thor/actions.rb
index d5ebdd194..08f1bb608 100644
--- a/lib/thor/actions.rb
+++ b/lib/thor/actions.rb
@@ -1,6 +1,5 @@
 require "uri"
 require "open3"
-require_relative "core_ext/io_binary_read"
 require_relative "actions/create_file"
 require_relative "actions/create_link"
 require_relative "actions/directory"
diff --git a/lib/thor/core_ext/io_binary_read.rb b/lib/thor/core_ext/io_binary_read.rb
deleted file mode 100644
index 0f6e2e0af..000000000
--- a/lib/thor/core_ext/io_binary_read.rb
+++ /dev/null
@@ -1,12 +0,0 @@
-class IO #:nodoc:
-  class << self
-    unless method_defined? :binread
-      def binread(file, *args)
-        raise ArgumentError, "wrong number of arguments (#{1 + args.size} for 1..3)" unless args.size < 3
-        File.open(file, "rb") do |f|
-          f.read(*args)
-        end
-      end
-    end
-  end
-end
diff --git a/lib/thor/runner.rb b/lib/thor/runner.rb
index a40634467..7b1b8d9b1 100644
--- a/lib/thor/runner.rb
+++ b/lib/thor/runner.rb
@@ -1,6 +1,5 @@
 require_relative "../thor"
 require_relative "group"
-require_relative "core_ext/io_binary_read"
 
 require "yaml"
 require "digest/md5"