diff --git a/Gemfile b/Gemfile
index 03ff03f6..8a8c541d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -24,6 +24,7 @@ gem "activesupport", "~> 6.1"
 gem 'redcarpet', platforms: [ :ruby ]
 gem 'rdiscount', platforms: [ :ruby ]
 gem 'puma'
+gem 'falcon', '~> 0.40', platforms: [ :ruby ]
 gem 'yajl-ruby', platforms: [ :ruby ]
 gem 'nokogiri', '> 1.5.0'
 gem 'rainbows', platforms: [ :ruby ]
@@ -40,7 +41,6 @@ gem 'rabl'
 gem 'builder'
 gem 'erubi'
 gem 'haml', '~> 5'
-gem 'celluloid', '~> 0.16.0'
 gem 'commonmarker', '~> 0.20.0', platforms: [ :ruby ]
 gem 'pandoc-ruby', '~> 2.0.2'
 gem 'simplecov', require: false
diff --git a/lib/sinatra/base.rb b/lib/sinatra/base.rb
index 97c6b2c5..57bf2201 100644
--- a/lib/sinatra/base.rb
+++ b/lib/sinatra/base.rb
@@ -1458,7 +1458,7 @@ module Sinatra
       alias_method :stop!, :quit!
 
       # Run the Sinatra app as a self-hosted server using
-      # Puma, Mongrel, or WEBrick (in that order). If given a block, will call
+      # Puma, Falcon, Mongrel, or WEBrick (in that order). If given a block, will call
       # with the constructed handler once we have taken the stage.
       def run!(options = {}, &block)
         return if running?
@@ -1801,6 +1801,7 @@ module Sinatra
     ruby_engine = defined?(RUBY_ENGINE) && RUBY_ENGINE
 
     server.unshift 'puma'
+    server.unshift 'falcon'   if ruby_engine != 'jruby'
     server.unshift 'mongrel'  if ruby_engine.nil?
     server.unshift 'thin'     if ruby_engine != 'jruby'
     server.unshift 'trinidad' if ruby_engine == 'jruby'
diff --git a/test/integration_helper.rb b/test/integration_helper.rb
index 5bdaa5d3..aed31a69 100644
--- a/test/integration_helper.rb
+++ b/test/integration_helper.rb
@@ -81,6 +81,10 @@ module IntegrationHelper
       name.to_s == "puma"
     end
 
+    def falcon?
+      name.to_s == "falcon"
+    end
+
     def trinidad?
       name.to_s == "trinidad"
     end
diff --git a/test/integration_test.rb b/test/integration_test.rb
index e174af53..f7069d51 100644
--- a/test/integration_test.rb
+++ b/test/integration_test.rb
@@ -13,7 +13,7 @@ class IntegrationTest < Minitest::Test
   it('only extends main') { assert_equal "true", server.get("/mainonly") }
 
   it 'logs once in development mode' do
-    next if server.puma? or server.rainbows? or RUBY_ENGINE == 'jruby'
+    next if server.puma? or server.falcon? or server.rainbows? or RUBY_ENGINE == 'jruby'
     random = "%064x" % Kernel.rand(2**256-1)
     server.get "/ping?x=#{random}"
     count = server.log.scan("GET /ping?x=#{random}").count
diff --git a/test/settings_test.rb b/test/settings_test.rb
index 69fc3d27..10d9796b 100644
--- a/test/settings_test.rb
+++ b/test/settings_test.rb
@@ -488,6 +488,16 @@ class SettingsTest < Minitest::Test
       assert @base.server.include?('puma')
       assert @application.server.include?('puma')
     end
+
+    it 'includes falcon on mruby' do
+      if RUBY_ENGINE == 'ruby'
+        assert @base.server.include?('falcon')
+        assert @application.server.include?('falcon')
+      else
+        assert !@base.server.include?('falcon')
+        assert !@application.server.include?('falcon')
+      end
+    end
   end
 
   describe 'app_file' do