diff --git a/activerecord/lib/active_record/fixtures.rb b/activerecord/lib/active_record/fixtures.rb
index eb89e3875f..a7a40ca72b 100644
--- a/activerecord/lib/active_record/fixtures.rb
+++ b/activerecord/lib/active_record/fixtures.rb
@@ -455,7 +455,7 @@ module ActiveRecord
             fixtures_map[fs_name] = new( # ActiveRecord::FixtureSet.new
               connection,
               fs_name,
-              class_names[fs_name] || default_fixture_model_name(fs_name),
+              class_names[fs_name] || (default_fixture_model_name(fs_name).safe_constantize),
               ::File.join(fixtures_directory, fs_name))
           end
 
@@ -504,11 +504,14 @@ module ActiveRecord
       @name     = name
       @path     = path
 
+      if class_name.is_a?(String)
+        ActiveSupport::Deprecation.warn("The ability to pass in strings as a class name will be removed in Rails 4.2, consider using the class itself instead.")
+      end
+
       if class_name.is_a?(Class) # TODO: Should be an AR::Base type class, or any?
         @model_class = class_name
       else
-        ActiveSupport::Deprecation.warn("The ability to pass in strings as a class name will be removed in Rails 4.1, consider using the class itself instead.")
-        @model_class = class_name.constantize rescue nil
+        @model_class = class_name.safe_constantize if class_name
       end
 
       @connection  = ( model_class.respond_to?(:connection) ?
diff --git a/activerecord/test/cases/fixtures_test.rb b/activerecord/test/cases/fixtures_test.rb
index c07c9c3b74..afbe65062d 100644
--- a/activerecord/test/cases/fixtures_test.rb
+++ b/activerecord/test/cases/fixtures_test.rb
@@ -190,11 +190,11 @@ class FixturesTest < ActiveRecord::TestCase
   end
 
   def test_empty_yaml_fixture
-    assert_not_nil ActiveRecord::FixtureSet.new( Account.connection, "accounts", 'Account', FIXTURES_ROOT + "/naked/yml/accounts")
+    assert_not_nil ActiveRecord::FixtureSet.new( Account.connection, "accounts", Account, FIXTURES_ROOT + "/naked/yml/accounts")
   end
 
   def test_empty_yaml_fixture_with_a_comment_in_it
-    assert_not_nil ActiveRecord::FixtureSet.new( Account.connection, "companies", 'Company', FIXTURES_ROOT + "/naked/yml/companies")
+    assert_not_nil ActiveRecord::FixtureSet.new( Account.connection, "companies", Company, FIXTURES_ROOT + "/naked/yml/companies")
   end
 
   def test_nonexistent_fixture_file
@@ -204,19 +204,19 @@ class FixturesTest < ActiveRecord::TestCase
     assert Dir[nonexistent_fixture_path+"*"].empty?
 
     assert_raise(Errno::ENOENT) do
-      ActiveRecord::FixtureSet.new( Account.connection, "companies", 'Company', nonexistent_fixture_path)
+      ActiveRecord::FixtureSet.new( Account.connection, "companies", Company, nonexistent_fixture_path)
     end
   end
 
   def test_dirty_dirty_yaml_file
     assert_raise(ActiveRecord::Fixture::FormatError) do
-      ActiveRecord::FixtureSet.new( Account.connection, "courses", 'Course', FIXTURES_ROOT + "/naked/yml/courses")
+      ActiveRecord::FixtureSet.new( Account.connection, "courses", Course, FIXTURES_ROOT + "/naked/yml/courses")
     end
   end
 
   def test_omap_fixtures
     assert_nothing_raised do
-      fixtures = ActiveRecord::FixtureSet.new(Account.connection, 'categories', 'Category', FIXTURES_ROOT + "/categories_ordered")
+      fixtures = ActiveRecord::FixtureSet.new(Account.connection, 'categories', Category, FIXTURES_ROOT + "/categories_ordered")
 
       fixtures.each.with_index do |(name, fixture), i|
         assert_equal "fixture_no_#{i}", name
@@ -449,7 +449,7 @@ class OverRideFixtureMethodTest < ActiveRecord::TestCase
 end
 
 class CheckSetTableNameFixturesTest < ActiveRecord::TestCase
-  set_fixture_class :funny_jokes => 'Joke'
+  set_fixture_class :funny_jokes => Joke
   fixtures :funny_jokes
   # Set to false to blow away fixtures cache and ensure our fixtures are loaded
   # and thus takes into account our set_fixture_class
@@ -532,7 +532,7 @@ class InvalidTableNameFixturesTest < ActiveRecord::TestCase
 end
 
 class CheckEscapedYamlFixturesTest < ActiveRecord::TestCase
-  set_fixture_class :funny_jokes => 'Joke'
+  set_fixture_class :funny_jokes => Joke
   fixtures :funny_jokes
   # Set to false to blow away fixtures cache and ensure our fixtures are loaded
   # and thus takes into account our set_fixture_class
diff --git a/guides/source/active_record_basics.md b/guides/source/active_record_basics.md
index bff60efc33..a80c3b6c8e 100644
--- a/guides/source/active_record_basics.md
+++ b/guides/source/active_record_basics.md
@@ -181,7 +181,7 @@ definition:
 
 ```ruby
 class FunnyJoke < ActiveSupport::TestCase
-  set_fixture_class funny_jokes: 'Joke'
+  set_fixture_class funny_jokes: Joke
   fixtures :funny_jokes
   ...
 end