diff --git a/.travis.yml b/.travis.yml
index d242c451..71a4d16c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -24,8 +24,10 @@ install:
   - export CXX="g++-8" CC="gcc-8"
   # Build Boost.
   - wget https://raw.githubusercontent.com/Ortham/ci-scripts/2.1.2/install_boost.py
-  - python install_boost.py --directory ~ --boost-version 1.67.0 -a 64 -t gcc-8 locale system
+  - python3 install_boost.py --directory ~ --boost-version 1.67.0 -a 64 -t gcc-8 locale system
   # Install packages for generating documentation
+  - pyenv install 3.6.3
+  - pyenv global 3.6.3
   - pip install --user -r docs/requirements.txt
   # Add sphinx-build to PATH
   - export PATH="$HOME/.local/bin:$PATH"