diff --git a/tox.ini b/tox.ini
index 59082d4..1eea21c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -35,6 +35,7 @@ deps =
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/doc/requirements.txt
 commands =
+  rm -rf doc/build
   sphinx-build -b html doc/source doc/build/html
 
 [testenv:releasenotes]
@@ -43,6 +44,7 @@ deps =
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/doc/requirements.txt
 commands =
+  rm -rf releasenotes/build
   sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
 
 [testenv:debug]