diff --git a/docs/topics/downloader-middleware.rst b/docs/topics/downloader-middleware.rst
index 0845ef6e4..be96425cf 100644
--- a/docs/topics/downloader-middleware.rst
+++ b/docs/topics/downloader-middleware.rst
@@ -513,7 +513,7 @@ defines the methods described below.
 
     .. method:: open_spider(spider)
 
-      This method gets called after a spider has been opened for crawling. It handles 
+      This method gets called after a spider has been opened for crawling. It handles
       the :signal:`open_spider <spider_opened>` signal.
 
       :param spider: the spider which has been opened
@@ -521,8 +521,8 @@ defines the methods described below.
 
     .. method:: close_spider(spider)
 
-      This method gets called after a spider has been closed. It handles 
-      the :signal:`close_spider <spider_closed>` signal. 
+      This method gets called after a spider has been closed. It handles
+      the :signal:`close_spider <spider_closed>` signal.
 
       :param spider: the spider which has been closed
       :type spider: :class:`~scrapy.spiders.Spider` object
@@ -1020,10 +1020,10 @@ the request will be ignored by this middleware even if
 RobotFileParser
 ~~~~~~~~~~~~~~~
 
-`RobotFileParser <https://docs.python.org/3.7/library/urllib.robotparser.html>`_ is 
-Python's inbuilt robots.txt_ parser. The parser is fully compliant with `Martijn Koster's 
+`RobotFileParser <https://docs.python.org/3.7/library/urllib.robotparser.html>`_ is
+Python's inbuilt robots.txt_ parser. The parser is fully compliant with `Martijn Koster's
 1996 draft specification <http://www.robotstxt.org/norobots-rfc.txt>`_. It lacks
-support for wildcard matching. Scrapy uses this parser by default.
+support for wildcard matching.
 
 In order to use this parser, set:
 
@@ -1074,13 +1074,12 @@ Protego parser
 
 `Protego <https://github.com/scrapy/protego>`_ is a pure-Python robots.txt_ parser.
 The parser is fully compliant with `Google's Robots.txt Specification
-<https://developers.google.com/search/reference/robots_txt>`_ hence supports wildcard 
+<https://developers.google.com/search/reference/robots_txt>`_ hence supports wildcard
 matching, and uses the length based rule similar to `Reppy <https://github.com/seomoz/reppy/>`_.
+Scrapy uses this parser by default.
 
 In order to use this parser:
 
-* Install `Protego <https://github.com/scrapy/protego>`_ by running ``pip install protego``
-
 * Set :setting:`ROBOTSTXT_PARSER` setting to
   ``scrapy.robotstxt.ProtegoRobotParser``
 
diff --git a/requirements-py2.txt b/requirements-py2.txt
index 9e6944240..61176bdba 100644
--- a/requirements-py2.txt
+++ b/requirements-py2.txt
@@ -15,3 +15,4 @@ service_identity>=16.0.0
 six>=1.10.0
 Twisted>=16.0.0
 zope.interface>=4.1.3
+protego
diff --git a/requirements-py3.txt b/requirements-py3.txt
index cd183a525..61e2e32d8 100644
--- a/requirements-py3.txt
+++ b/requirements-py3.txt
@@ -15,3 +15,4 @@ lxml>=3.5.0
 service_identity>=16.0.0
 six>=1.10.0
 zope.interface>=4.1.3
+protego
diff --git a/scrapy/settings/default_settings.py b/scrapy/settings/default_settings.py
index 05ab4b628..9c22999cb 100644
--- a/scrapy/settings/default_settings.py
+++ b/scrapy/settings/default_settings.py
@@ -246,7 +246,7 @@ RETRY_HTTP_CODES = [500, 502, 503, 504, 522, 524, 408, 429]
 RETRY_PRIORITY_ADJUST = -1
 
 ROBOTSTXT_OBEY = False
-ROBOTSTXT_PARSER = 'scrapy.robotstxt.PythonRobotParser'
+ROBOTSTXT_PARSER = 'scrapy.robotstxt.ProtegoRobotParser'
 ROBOTSTXT_USER_AGENT = None
 
 SCHEDULER = 'scrapy.core.scheduler.Scheduler'
diff --git a/tox.ini b/tox.ini
index cc845faf1..c3502c2ca 100644
--- a/tox.ini
+++ b/tox.ini
@@ -125,7 +125,6 @@ deps =
     {[testenv:py35]deps}
     reppy
     robotexclusionrulesparser
-    protego
 
 [testenv:py27-extra-deps]
 basepython = python2.7
@@ -133,4 +132,3 @@ deps =
     {[testenv]deps}
     reppy
     robotexclusionrulesparser
-    protego
\ No newline at end of file