diff --git a/ChangeLog b/ChangeLog
index 01fbd80534..2d1029b21c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Jun 15 01:44:42 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* tool/mkconfig.rb: provide Unicode Version information as
+	  RbConfig::CONFIG['UNICODE_VERSION'].
+	  [ruby-core:75845] [Feature #12460]
+
 Wed Jun 15 00:01:18 2016  Kazuhiro NISHIYAMA  <zn@mbf.nifty.com>
 
 	* test/ruby/enc/test_case_comprehensive.rb
diff --git a/common.mk b/common.mk
index 5eb5205550..44786122b5 100644
--- a/common.mk
+++ b/common.mk
@@ -628,7 +628,9 @@ $(RBCONFIG): $(srcdir)/tool/mkconfig.rb config.status $(srcdir)/version.h
 		-cross_compiling=$(CROSS_COMPILING) \
 		-arch=$(arch) -version=$(RUBY_PROGRAM_VERSION) \
 		-install_name=$(RUBY_INSTALL_NAME) \
-		-so_name=$(RUBY_SO_NAME) > rbconfig.tmp
+		-so_name=$(RUBY_SO_NAME) \
+		-unicode_version=$(UNICODE_VERSION) \
+	> rbconfig.tmp
 	$(IFCHANGE) "--timestamp=$@" rbconfig.rb rbconfig.tmp
 
 test-rubyspec-precheck:
diff --git a/tool/mkconfig.rb b/tool/mkconfig.rb
index 566f5a304e..6b6f14c940 100755
--- a/tool/mkconfig.rb
+++ b/tool/mkconfig.rb
@@ -9,6 +9,7 @@
 $install_name ||= nil
 $so_name ||= nil
 $cross_compiling ||= nil
+$unicode_version ||= nil
 arch = $arch or raise "missing -arch"
 version = $version or raise "missing -version"
 
@@ -235,6 +236,9 @@ end
 
 print(*v_fast)
 print(*v_others)
+print <<EOS if $unicode_version
+  CONFIG["UNICODE_VERSION"] = #{$unicode_version.dump}
+EOS
 print <<EOS if /darwin/ =~ arch
   CONFIG["SDKROOT"] = ENV["SDKROOT"] || "" # don't run xcrun everytime, usually useless.
 EOS