diff --git a/Gemfile b/Gemfile
index d6bc22a78..5da32e43c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -47,7 +47,8 @@ if File.exist?(database_file)
       case adapter
       when /mysql/
         gem "mysql", "~> 2.8.1", :platforms => [:mri_18, :mingw_18]
-        gem "mysql2", "~> 0.3.11", :platforms => [:mri_19, :mingw_19, :mri_20, :mingw_20]
+        mysql2_platforms = RUBY_VERSION >= '2.0' ? [:mri_20, :mingw_20] : [:mri_19, :mingw_19]
+        gem "mysql2", "~> 0.3.11", :platforms => mysql2_platforms
         gem "activerecord-jdbcmysql-adapter", :platforms => :jruby
       when /postgresql/
         gem "pg", ">= 0.11.0", :platforms => [:mri, :mingw]