diff --git a/activemodel/lib/active_model/attribute_methods.rb b/activemodel/lib/active_model/attribute_methods.rb
index 98cde8ba59198a760464fba76ff630806f9e5c58..986a7ade810d9bb875f7bbe690d52c5dd07fae53 100644
--- a/activemodel/lib/active_model/attribute_methods.rb
+++ b/activemodel/lib/active_model/attribute_methods.rb
@@ -388,14 +388,6 @@ class AttributeMethodMatcher #:nodoc:
           AttributeMethodMatch = Struct.new(:target, :attr_name, :method_name)
 
           def initialize(options = {})
-            if options[:prefix] == '' || options[:suffix] == ''
-              message = "Specifying an empty prefix/suffix for an attribute method is no longer " \
-                        "necessary. If the un-prefixed/suffixed version of the method has not been " \
-                        "defined when `define_attribute_methods` is called, it will be defined " \
-                        "automatically."
-              ActiveSupport::Deprecation.warn message
-            end
-
             @prefix, @suffix = options.fetch(:prefix, ''), options.fetch(:suffix, '')
             @regex = /^(?:#{Regexp.escape(@prefix)})(.*)(?:#{Regexp.escape(@suffix)})$/
             @method_missing_target = "#{@prefix}attribute#{@suffix}"
diff --git a/activemodel/test/cases/attribute_methods_test.rb b/activemodel/test/cases/attribute_methods_test.rb
index 25eb4860e32a8f86d4ac673d65fe7601ed4b88a9..e9cb5ccc96aad8c9ebedf4f1114490f0be03e600 100644
--- a/activemodel/test/cases/attribute_methods_test.rb
+++ b/activemodel/test/cases/attribute_methods_test.rb
@@ -202,17 +202,6 @@ def foo
     assert_equal 'bar', m.foo_test
   end
 
-  test 'explicitly specifying an empty prefix/suffix is deprecated' do
-    klass = Class.new(ModelWithAttributes)
-
-    assert_deprecated { klass.attribute_method_suffix '' }
-    assert_deprecated { klass.attribute_method_prefix '' }
-
-    klass.define_attribute_methods(:foo)
-
-    assert_equal 'value of foo', klass.new.foo
-  end
-
   test 'should not interfere with method_missing if the attr has a private/protected method' do
     m = ModelWithAttributes2.new
     m.attributes = { 'private_method' => '<3', 'protected_method' => 'O_o' }