diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index 0e0011e01..a986d43d5 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -125,6 +125,11 @@ If you want to lint the entire code base run::
 
     $ pylint $(find tests xonsh -name \*.py | sort)
 
+We also use ``black`` for formatting the code base (which includes running in
+our tests)::
+
+    $ black --check --exclude=xonsh/ply/ xonsh/ xontrib/
+
 **********
 Imports
 **********
diff --git a/requirements-docs.txt b/requirements-docs.txt
index 70125f9c2..748489119 100644
--- a/requirements-docs.txt
+++ b/requirements-docs.txt
@@ -8,3 +8,4 @@ pyzmq
 matplotlib
 doctr
 tornado
+black
diff --git a/requirements-tests.txt b/requirements-tests.txt
index 391e3e3d1..6f5b32f41 100644
--- a/requirements-tests.txt
+++ b/requirements-tests.txt
@@ -8,3 +8,4 @@ prompt-toolkit
 pygments>=2.2
 codecov
 coverage
+black