diff --git a/doc/readthedocs_requirements.txt b/doc/readthedocs_requirements.txt
index 991ce2d25..f83d190d3 100644
--- a/doc/readthedocs_requirements.txt
+++ b/doc/readthedocs_requirements.txt
@@ -4,3 +4,4 @@
 -r ../requirements.txt
 -r ../extra-requirements.txt
 -r ./requirements.txt
+sphinx_rtd_theme>=0.5.1,<1    # Apache-2.0
diff --git a/doc/source/conf.py b/doc/source/conf.py
index b2dab34b9..0615d5110 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -56,13 +56,6 @@ release = get_version.get_version()
 version = '.'.join(release.split('.', 2)[:2])
 
 
-# -- Install requirements ----------------------------------------------------
-
-from tools import install
-install.pip_install('sphinx_rtd_theme>=0.5.1,<1')   # Apache-2.0
-install.install_tobiko()
-
-
 # -- General configuration ---------------------------------------------------
 
 # Add any Sphinx extension module names here, as strings. They can be
diff --git a/tox.ini b/tox.ini
index 54e49bc2b..56e61d2b8 100644
--- a/tox.ini
+++ b/tox.ini
@@ -275,8 +275,9 @@ basepython = {[testenv:py3]basepython}
 envdir = {toxworkdir}/docs
 deps =
     {env:TOX_CONSTRAINTS}
-    -r{toxinidir}/doc/requirements.txt
-
+    -r{toxinidir}/doc/readthedocs_requirements.txt
+commands =
+    {envpython} -m pip install {env:TOX_CONSTRAINTS} {toxinidir}
 
 [testenv:linkcheck]
 
@@ -285,6 +286,7 @@ basepython = {[docs]basepython}
 envdir = {[docs]envdir}
 deps = {[docs]deps}
 commands =
+    {[docs]commands}
     sh -c 'cd {toxinidir}/doc/source && sphinx-build -W -b linkcheck . ../build/linkcheck'
 # Do not install any requirements. We want this to be fast and work even if
 # system dependencies are missing, since it's used to tell you what system