diff --git a/Dockerfile b/Dockerfile
index c7b697b..37f6cc8 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -11,8 +11,9 @@ RUN src/scripts/download_vim.sh
 COPY scripts/build_vim.sh src/scripts/
 RUN src/scripts/build_vim.sh
 
-# We clone the plugins we currently depend on manually here. Initially we check if their master
-# has changed since last time we build, this will invalidate the cache.
+# We clone the plugins we currently depend on manually here. Initially we check
+# if their master has changed since last time we build, this will invalidate
+# the cache.
 RUN mkdir -p /tmp/UltiSnips_test_vim_plugins
 
 ADD https://api.github.com/repos/tpope/vim-pathogen/git/refs/heads/master \
@@ -23,5 +24,13 @@ ADD https://api.github.com/repos/ervandew/supertab/git/refs/heads/master \
     /src/scripts/supertab_version.json
 RUN git clone --recursive --depth 1 https://github.com/ervandew/supertab /tmp/UltiSnips_test_vim_plugins/supertab
 
+# Unidecode is not a Vim plugin, but a Python library we depend on. We also
+# install the latest version through pip. But we still use GitHub activity as a
+# marker to invalidate the installation step, just to make sure we occasionally
+# reinstall a new version.
+ADD https://api.github.com/repos/avian2/unidecode/git/refs/heads/master \
+    /src/scripts/unidecode_version.json
+RUN pip install unidecode
+
 COPY . /src/UltiSnips
 WORKDIR /src/UltiSnips