diff --git a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
index bfdc7995f0..4c57bd48ab 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
@@ -3,7 +3,7 @@
 require "active_record/connection_adapters/abstract_mysql_adapter"
 require "active_record/connection_adapters/mysql/database_statements"
 
-gem "mysql2", "~> 0.4.4"
+gem "mysql2", ">= 0.4.4", "< 0.6.0"
 require "mysql2"
 
 module ActiveRecord
diff --git a/railties/lib/rails/generators/app_base.rb b/railties/lib/rails/generators/app_base.rb
index e1889979d7..8c5d872573 100644
--- a/railties/lib/rails/generators/app_base.rb
+++ b/railties/lib/rails/generators/app_base.rb
@@ -299,7 +299,7 @@ module Rails
       def gem_for_database
         # %w( mysql postgresql sqlite3 oracle frontbase ibm_db sqlserver jdbcmysql jdbcsqlite3 jdbcpostgresql )
         case options[:database]
-        when "mysql"          then ["mysql2", ["~> 0.4.4"]]
+        when "mysql"          then ["mysql2", [">= 0.4.4", "< 0.6.0"]]
         when "postgresql"     then ["pg", [">= 0.18", "< 2.0"]]
         when "oracle"         then ["activerecord-oracle_enhanced-adapter", nil]
         when "frontbase"      then ["ruby-frontbase", nil]