diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 756a0d7196..606ff7eca0 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,5 +1,10 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Rename `ActiveRecord::Model::Tag` to `ActiveRecord::Tag`.
+    Fix #7714.
+
+    *Francesco Rodriguez*
+
 *   `ActiveModel::ForbiddenAttributesProtection` is included by default
     in Active Record models. Check the docs of `ActiveModel::ForbiddenAttributesProtection`
     for more details.
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
index f42a5df75f..42bd16db80 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -6,7 +6,7 @@ require 'active_support/core_ext/module/deprecation'
 module ActiveRecord
   # Raised when a connection could not be obtained within the connection
   # acquisition timeout period: because max connections in pool
-  # are in use. 
+  # are in use.
   class ConnectionTimeoutError < ConnectionNotEstablished
   end
 
@@ -417,7 +417,7 @@ module ActiveRecord
       # queue for a connection to become available.
       #
       # Raises:
-      # - ConnectionTimeoutError if a connection could not be acquired 
+      # - ConnectionTimeoutError if a connection could not be acquired
       def acquire_connection
         if conn = @available.poll
           conn
@@ -567,7 +567,7 @@ module ActiveRecord
         class_to_pool[klass] ||= begin
           until pool = pool_for(klass)
             klass = klass.superclass
-            break unless klass < Model::Tag
+            break unless klass < ActiveRecord::Tag
           end
 
           class_to_pool[klass] = pool || pool_for(ActiveRecord::Model)
diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb
index 04fff99a6e..35273b0d81 100644
--- a/activerecord/lib/active_record/inheritance.rb
+++ b/activerecord/lib/active_record/inheritance.rb
@@ -50,7 +50,7 @@ module ActiveRecord
       # If B < A and C < B and if A is an abstract_class then both B.base_class
       # and C.base_class would return B as the answer since A is an abstract_class.
       def base_class
-        unless self < Model::Tag
+        unless self < ActiveRecord::Tag
           raise ActiveRecordError, "#{name} doesn't belong in a hierarchy descending from ActiveRecord"
         end
 
@@ -73,7 +73,7 @@ module ActiveRecord
       #   class Child < SuperClass
       #     self.table_name = 'the_table_i_really_want'
       #   end
-      # 
+      #
       #
       # <tt>self.abstract_class = true</tt> is required to make <tt>Child<.find,.create, or any Arel method></tt> use <tt>the_table_i_really_want</tt> instead of a table called <tt>super_classes</tt>
       #
diff --git a/activerecord/lib/active_record/model.rb b/activerecord/lib/active_record/model.rb
index 44cde49bd5..16d9d404e3 100644
--- a/activerecord/lib/active_record/model.rb
+++ b/activerecord/lib/active_record/model.rb
@@ -26,21 +26,21 @@ module ActiveRecord
     end
   end
 
-  # <tt>ActiveRecord::Model</tt> can be included into a class to add Active Record persistence.
-  # This is an alternative to inheriting from <tt>ActiveRecord::Base</tt>. Example:
+  # This allows us to detect an ActiveRecord::Model while it's in the process of
+  # being included.
+  module Tag; end
+
+  # <tt>ActiveRecord::Model</tt> can be included into a class to add Active Record
+  # persistence. This is an alternative to inheriting from <tt>ActiveRecord::Base</tt>.
   #
   #     class Post
   #       include ActiveRecord::Model
   #     end
-  #
   module Model
     extend ActiveSupport::Concern
     extend ConnectionHandling
     extend ActiveModel::Observing::ClassMethods
 
-    # This allows us to detect an ActiveRecord::Model while it's in the process of being included.
-    module Tag; end
-
     def self.append_features(base)
       base.class_eval do
         include Tag
diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
index 263fdce250..71030cb5d7 100644
--- a/activerecord/lib/active_record/relation/predicate_builder.rb
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -40,7 +40,7 @@ module ActiveRecord
       #
       # For polymorphic relationships, find the foreign key and type:
       # PriceEstimate.where(:estimate_of => treasure)
-      if klass && value.class < Model::Tag && reflection = klass.reflect_on_association(column.to_sym)
+      if klass && value.class < ActiveRecord::Tag && reflection = klass.reflect_on_association(column.to_sym)
         if reflection.polymorphic?
           queries << build(table[reflection.foreign_type], value.class.base_class)
         end
diff --git a/activerecord/test/cases/connection_adapters/connection_handler_test.rb b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
index e1579d037f..4467ddfc39 100644
--- a/activerecord/test/cases/connection_adapters/connection_handler_test.rb
+++ b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
@@ -4,8 +4,8 @@ module ActiveRecord
   module ConnectionAdapters
     class ConnectionHandlerTest < ActiveRecord::TestCase
       def setup
-        @klass    = Class.new { include Model::Tag }
-        @subklass = Class.new(@klass) { include Model::Tag }
+        @klass    = Class.new { include ActiveRecord::Tag }
+        @subklass = Class.new(@klass) { include ActiveRecord::Tag }
 
         @handler = ConnectionHandler.new
         @handler.establish_connection @klass, Base.connection_pool.spec