diff --git a/.rspec b/.rspec
new file mode 100644
index 0000000..2559e39
--- /dev/null
+++ b/.rspec
@@ -0,0 +1,3 @@
+--color
+--format progress
+--require spec_helper
diff --git a/Rakefile b/Rakefile
index dfe61c2..6b5fb85 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,5 +1,6 @@
 require 'bundler/setup'
 require 'cucumber/rake/task'
+require 'rspec/core/rake_task'
 
 Bundler::GemHelper.install_tasks name: 'factory_bot_rails'
 
@@ -8,12 +9,14 @@ Cucumber::Rake::Task.new(:cucumber) do |t|
   t.cucumber_opts = ['--format', (ENV['CUCUMBER_FORMAT'] || 'progress')]
 end
 
+RSpec::Core::RakeTask.new(:spec)
+
 require 'appraisal'
 
 desc 'Run the test suite'
 task :default do |t|
   if ENV['BUNDLE_GEMFILE'] =~ /gemfiles/
-    exec 'rake cucumber'
+    exec 'rake spec && rake cucumber'
   else
     Rake::Task['appraise'].execute
   end
diff --git a/lib/factory_bot_rails/definition_file_paths.rb b/lib/factory_bot_rails/definition_file_paths.rb
new file mode 100644
index 0000000..dd0178b
--- /dev/null
+++ b/lib/factory_bot_rails/definition_file_paths.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module FactoryBotRails
+  class DefinitionFilePaths
+    attr_reader :files, :directories
+
+    def initialize(definition_file_paths)
+      @files = []
+      @directories = {}
+
+      definition_file_paths.each do |path|
+        @files << "#{path}.rb"
+        @directories[path.to_s] = [:rb]
+      end
+    end
+  end
+end
diff --git a/lib/factory_bot_rails/railtie.rb b/lib/factory_bot_rails/railtie.rb
index f7af2b0..bd39882 100644
--- a/lib/factory_bot_rails/railtie.rb
+++ b/lib/factory_bot_rails/railtie.rb
@@ -1,28 +1,31 @@
-require 'factory_bot'
-require 'factory_bot_rails/generator'
-require 'rails'
+# frozen_string_literal: true
 
-module FactoryBot
+require "factory_bot"
+require "factory_bot_rails/generator"
+require "factory_bot_rails/reloader"
+require "rails"
+
+module FactoryBotRails
   class Railtie < Rails::Railtie
 
     initializer "factory_bot.set_fixture_replacement" do
-      FactoryBotRails::Generator.new(config).run
+      Generator.new(config).run
     end
 
     initializer "factory_bot.set_factory_paths" do
       FactoryBot.definition_file_paths = [
-        Rails.root.join('factories'),
-        Rails.root.join('test', 'factories'),
-        Rails.root.join('spec', 'factories')
+        Rails.root.join("factories"),
+        Rails.root.join("test", "factories"),
+        Rails.root.join("spec", "factories"),
       ]
     end
 
+    initializer "factory_bot.register_reloader" do |app|
+      Reloader.new(app, config).run
+    end
+
     config.after_initialize do
       FactoryBot.find_definitions
-
-      if defined?(Spring)
-        Spring.after_fork { FactoryBot.reload }
-      end
     end
   end
 end
diff --git a/lib/factory_bot_rails/reloader.rb b/lib/factory_bot_rails/reloader.rb
new file mode 100644
index 0000000..329ac26
--- /dev/null
+++ b/lib/factory_bot_rails/reloader.rb
@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+require "factory_bot_rails/definition_file_paths"
+
+module FactoryBotRails
+  class Reloader
+    def initialize(app, config)
+      @app = app
+      @config = config
+    end
+
+    def run
+      register_reloader(build_reloader)
+    end
+
+    private
+
+    attr_reader :app, :config
+
+    def build_reloader
+      paths = DefinitionFilePaths.new(FactoryBot.definition_file_paths)
+
+      reloader_class.new(paths.files, paths.directories) do
+        FactoryBot.reload
+      end
+    end
+
+    def reloader_class
+      app.config.file_watcher
+    end
+
+    def register_reloader(reloader)
+      config.to_prepare do
+        reloader.execute_if_updated
+      end
+
+      app.reloaders << reloader
+    end
+  end
+end
diff --git a/lib/generators/factory_bot/model/model_generator.rb b/lib/generators/factory_bot/model/model_generator.rb
index d5a49eb..4db0e21 100644
--- a/lib/generators/factory_bot/model/model_generator.rb
+++ b/lib/generators/factory_bot/model/model_generator.rb
@@ -91,7 +91,7 @@ RUBY
       end
 
       def generators
-        config = FactoryBot::Railtie.config
+        config = FactoryBotRails::Railtie.config
         config.respond_to?(:app_generators) ? config.app_generators : config.generators
       end
     end
diff --git a/spec/factory_bot_rails/definition_file_paths_spec.rb b/spec/factory_bot_rails/definition_file_paths_spec.rb
new file mode 100644
index 0000000..68ccad6
--- /dev/null
+++ b/spec/factory_bot_rails/definition_file_paths_spec.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+describe FactoryBotRails::DefinitionFilePaths do
+  describe "#files" do
+    it "returns a list of definition files" do
+      definition_file_paths = ["definition_path", "another_definition_path"]
+
+      files = described_class.new(definition_file_paths).files
+
+      expect(files).to eq ["definition_path.rb", "another_definition_path.rb"]
+    end
+  end
+
+  describe "#directories" do
+    it "returns a hash of definition directories" do
+      definition_file_paths = ["definition_path", "another_definition_path"]
+
+      directories = described_class.new(definition_file_paths).directories
+
+      expect(directories).to eq(
+        "definition_path" => [:rb],
+        "another_definition_path" => [:rb],
+      )
+    end
+
+    it "converts Pathname objects to strings" do
+      definition_file_paths = [Pathname.new("definition_path")]
+
+      directories = described_class.new(definition_file_paths).directories
+
+      expect(directories).to eq("definition_path" => [:rb])
+    end
+  end
+end
diff --git a/spec/factory_bot_rails/railtie_spec.rb b/spec/factory_bot_rails/railtie_spec.rb
new file mode 100644
index 0000000..b03e680
--- /dev/null
+++ b/spec/factory_bot_rails/railtie_spec.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+describe FactoryBotRails::Railtie do
+  describe "application reloading" do
+    context "when a definition file has been updated" do
+      it "reloads the factory definitions" do
+        allow(FactoryBot).to receive(:reload)
+
+        touch("factories.rb")
+        reload_rails!
+
+        expect(FactoryBot).to have_received(:reload)
+      end
+    end
+
+    context "when a file in a definition directory has been updated" do
+      it "reloads the factory definitions" do
+        allow(FactoryBot).to receive(:reload)
+
+        touch("factories/definitions.rb")
+        reload_rails!
+
+        expect(FactoryBot).to have_received(:reload)
+      end
+    end
+
+    context "when the factory definitions have NOT been updated" do
+      it "does NOT reload the factory definitions" do
+        allow(FactoryBot).to receive(:reload)
+
+        reload_rails!
+
+        expect(FactoryBot).not_to have_received(:reload)
+      end
+    end
+
+    def touch(file)
+      FileUtils.touch(Rails.root.join(file))
+    end
+
+    def reload_rails!
+      if defined? ActiveSupport::Reloader
+        Rails.application.reloader.reload!
+      else
+        # For Rails 4
+        ActionDispatch::Reloader.cleanup!
+        ActionDispatch::Reloader.prepare!
+      end
+
+      wait_for_rails_to_reload
+    end
+
+    def wait_for_rails_to_reload
+      sleep 0.01
+    end
+  end
+end
diff --git a/spec/fake_app.rb b/spec/fake_app.rb
new file mode 100644
index 0000000..37e7b2a
--- /dev/null
+++ b/spec/fake_app.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module Dummy
+  class Application < Rails::Application
+    config.eager_load = false
+    config.root = "spec/fixtures"
+  end
+end
+
+Rails.logger = Logger.new("/dev/null")
+
+Rails.application.initialize!
diff --git a/spec/fixtures/factories.rb b/spec/fixtures/factories.rb
new file mode 100644
index 0000000..82e878d
--- /dev/null
+++ b/spec/fixtures/factories.rb
@@ -0,0 +1 @@
+# Rails.root.join('factories.rb')
diff --git a/spec/fixtures/factories/definitions.rb b/spec/fixtures/factories/definitions.rb
new file mode 100644
index 0000000..37149d4
--- /dev/null
+++ b/spec/fixtures/factories/definitions.rb
@@ -0,0 +1 @@
+# Rails.root.join('factories', 'definitions.rb')
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
new file mode 100644
index 0000000..5cbcde8
--- /dev/null
+++ b/spec/spec_helper.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+ENV["RAILS_ENV"] = "test"
+
+require "factory_bot_rails"
+require "fake_app"
+
+RSpec.configure do |config|
+  config.run_all_when_everything_filtered = true
+  config.filter_run :focus
+  config.order = "random"
+end