diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8c408eba..b7853cac 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 # Unreleased
 
+- Implement `rack.response_finished` (#97).
 - Don't break the `rack.after_reply` callback chain if one callback raises (#97).
 
 # 0.11.1
diff --git a/lib/pitchfork/http_server.rb b/lib/pitchfork/http_server.rb
index 6ad39df7..4b50255b 100644
--- a/lib/pitchfork/http_server.rb
+++ b/lib/pitchfork/http_server.rb
@@ -732,7 +732,7 @@ def process_client(client, worker, timeout_handler)
         end
       end
 
-      env["rack.after_reply"] = []
+      env["rack.response_finished"] = env["rack.after_reply"] = []
 
       status, headers, body = @app.call(env)
 
@@ -758,15 +758,19 @@ def process_client(client, worker, timeout_handler)
         client.close # flush and uncork socket immediately, no keepalive
       end
       env
-    rescue => e
-      handle_error(client, e)
+    rescue => application_error
+      handle_error(client, application_error)
       env
     ensure
       if env
-        env["rack.after_reply"].each do |callback|
-          callback.call
-        rescue => error
-          Pitchfork.log_error(@logger, "rack.after_reply error", error)
+        env["rack.response_finished"].each do |callback|
+          if callback.arity == 0
+            callback.call
+          else
+            callback.call(env, status, headers, application_error)
+          end
+        rescue => callback_error
+          Pitchfork.log_error(@logger, "rack.after_reply error", callback_error)
         end
       end
       timeout_handler.finished
diff --git a/test/slow/test_server.rb b/test/slow/test_server.rb
index 7118bb7e..8644411a 100644
--- a/test/slow/test_server.rb
+++ b/test/slow/test_server.rb
@@ -35,6 +35,7 @@ def call(env)
   class TestRackAfterReply
     def initialize
       @called = false
+      @valid_arguments = false
     end
 
     def call(env)
@@ -42,13 +43,23 @@ def call(env)
       end
 
       env["rack.after_reply"] << -> { raise "oops" }
+      env["rack.response_finished"] << method(:check_arguments)
       env["rack.after_reply"] << -> { @called = true }
 
-      [200, { 'content-type' => 'text/plain' }, ["after_reply_called: #{@called}"]]
+      [200, { 'content-type' => 'text/plain' }, ["after_reply_called: #{@called}\nresponse_finished_called: #{@valid_arguments}\n"]]
     rescue Pitchfork::ClientShutdown, Pitchfork::HttpParserError => e
       $stderr.syswrite("#{e.class}: #{e.message} #{e.backtrace.empty?}\n")
       raise e
     end
+
+    def check_arguments(env, status, headers, application_error)
+      return unless env.is_a?(Hash) && env["SERVER_PROTOCOL"]
+      return unless status == 200
+      return unless headers.is_a?(Hash) && headers.key?("content-type")
+      return unless application_error.nil?
+
+      @valid_arguments = true
+    end
   end
 
   def setup
@@ -142,6 +153,7 @@ def test_after_reply
     responses = sock.read(4096)
     assert_match %r{\AHTTP/1.[01] 200\b}, responses
     assert_match %r{^after_reply_called: false}, responses
+    assert_match %r{^response_finished_called: false}, responses
 
     sock = tcp_socket('127.0.0.1', @port)
     sock.syswrite("GET / HTTP/1.0\r\n\r\n")
@@ -149,6 +161,7 @@ def test_after_reply
     responses = sock.read(4096)
     assert_match %r{\AHTTP/1.[01] 200\b}, responses
     assert_match %r{^after_reply_called: true}, responses
+    assert_match %r{^response_finished_called: true}, responses
 
     sock.close
   end