diff --git a/lib/sinatra/base.rb b/lib/sinatra/base.rb
index 74260d5029..ed8f37d3ab 100644
--- a/lib/sinatra/base.rb
+++ b/lib/sinatra/base.rb
@@ -1416,7 +1416,7 @@ def unlink(path, opts = {}, &bk)  route 'UNLINK',  path, opts, &bk end
       # in `extensions` available to the handlers and templates
       def helpers(*extensions, &block)
         class_eval(&block)   if block_given?
-        include(*extensions) if extensions.any?
+        prepend(*extensions) if extensions.any?
       end
 
       # Register an extension. Alternatively take a block from which an
diff --git a/test/helpers_test.rb b/test/helpers_test.rb
index 3575e945cd..71703d92e8 100644
--- a/test/helpers_test.rb
+++ b/test/helpers_test.rb
@@ -1941,5 +1941,27 @@ def foo
       assert ok?
       assert_equal '42 < 43', body
     end
+
+    it 'prepends modules so previously-defined methods can be overridden consistently' do
+      mock_app do
+        helpers do
+          def one; nil; end
+          def two; nil; end
+        end
+
+        helpers ::HelperOne do
+          def two; '2' end
+        end
+
+        get('/one') { one }
+        get('/two') { two }
+      end
+
+      get '/one'
+      assert_equal '1', body
+
+      get '/two'
+      assert_equal '2', body
+    end
   end
 end