diff --git a/ChangeLog b/ChangeLog
index 28621c3d18..8d9da44de1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Fri Jan  1 03:26:44 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/ostruct.rb (freeze): define deferred accessors before
+	  freezing to get rid of an error when just reading frozen
+	  OpenStruct.
+
 Thu Dec 31 14:36:45 2015  Marc-Andre Lafortune  <ruby-core@marc-andre.ca>
 
 	* lib/ostruct.rb: Fix new_ostruct_member to correctly avoid
diff --git a/lib/ostruct.rb b/lib/ostruct.rb
index e5b69608ad..17efcdc8d3 100644
--- a/lib/ostruct.rb
+++ b/lib/ostruct.rb
@@ -176,6 +176,11 @@ class OpenStruct
   end
   protected :new_ostruct_member
 
+  def freeze
+    @table.each_key {|key| new_ostruct_member(key)}
+    super
+  end
+
   def respond_to_missing?(mid, include_private = false)
     mname = mid.to_s.chomp("=").to_sym
     @table.key?(mname) || super