diff --git a/middleman-core/lib/middleman-core/application.rb b/middleman-core/lib/middleman-core/application.rb
index 94e8c23f..d30e1625 100644
--- a/middleman-core/lib/middleman-core/application.rb
+++ b/middleman-core/lib/middleman-core/application.rb
@@ -148,9 +148,6 @@ module Middleman
     # Sitemap Config options and public api
     include Middleman::Sitemap
 
-    # Setup external helpers
-    include Middleman::CoreExtensions::ExternalHelpers
-
     # Reference to Logger singleton
     def logger
       ::Middleman::Logger.singleton
diff --git a/middleman-core/lib/middleman-core/core_extensions.rb b/middleman-core/lib/middleman-core/core_extensions.rb
index 64be17ef..1e3e738a 100644
--- a/middleman-core/lib/middleman-core/core_extensions.rb
+++ b/middleman-core/lib/middleman-core/core_extensions.rb
@@ -18,7 +18,10 @@ Middleman::Extensions.register :front_matter do
 end
 
 # External helpers looks in the helpers/ folder for helper modules
-require 'middleman-core/core_extensions/external_helpers'
+Middleman::Extensions.register :external_helpers, auto_activate_before_configuration: true  do
+  require 'middleman-core/core_extensions/external_helpers'
+  Middleman::CoreExtensions::ExternalHelpers
+end
 
 # Extended version of Padrino's rendering
 require 'middleman-core/core_extensions/rendering'
diff --git a/middleman-core/lib/middleman-core/core_extensions/external_helpers.rb b/middleman-core/lib/middleman-core/core_extensions/external_helpers.rb
index e4b41772..6b755df5 100644
--- a/middleman-core/lib/middleman-core/core_extensions/external_helpers.rb
+++ b/middleman-core/lib/middleman-core/core_extensions/external_helpers.rb
@@ -1,9 +1,10 @@
-# Load helpers in helpers/
 module Middleman
   module CoreExtensions
-    module ExternalHelpers
-      # once registered
-      def self.included(app)
+    # Load helpers in `helpers/`
+    class ExternalHelpers < Extension
+      def initialize(app, options_hash={}, &block)
+        super
+
         # Setup a default helpers paths
         app.config.define_setting :helpers_dir, 'helpers', 'Directory to autoload helper modules from'
         app.config.define_setting :helpers_filename_glob, '**.rb', 'Glob pattern for matching helper ruby files'
@@ -11,20 +12,20 @@ module Middleman
           basename = File.basename(filename, File.extname(filename))
           basename.camelcase
         }, 'Proc implementing the conversion from helper filename to module name'
+      end
 
-        # After config
-        app.after_configuration do
-          helpers_path = File.join(root, config[:helpers_dir])
-          next unless File.exist?(helpers_path)
+      def after_configuration
+        helpers_path = File.join(app.root, app.config[:helpers_dir])
 
-          Dir[File.join(helpers_path, config[:helpers_filename_glob])].each do |filename|
-            module_name = config[:helpers_filename_to_module_name_proc].call(filename)
+        if File.exist?(helpers_path)
+          Dir[File.join(helpers_path, app.config[:helpers_filename_glob])].each do |filename|
+            module_name = app.config[:helpers_filename_to_module_name_proc].call(filename)
             next unless module_name
 
             require filename
             next unless Object.const_defined?(module_name.to_sym)
 
-            @template_context_class.send :include, Object.const_get(module_name.to_sym)
+            app.template_context_class.send :include, Object.const_get(module_name.to_sym)
           end
         end
       end