diff --git a/.travis.yml b/.travis.yml
index 923f8c3d7..ee7539ca5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,7 @@ python:
 
 install:
     - pip install -e .[tests]
+    - pip install Cython
     - pip install -r requirements.txt
     - pip install codecov
     - pip install -r docs/requirements.txt
diff --git a/setup.py b/setup.py
index 8e8098c7d..32dc3ddfe 100644
--- a/setup.py
+++ b/setup.py
@@ -17,6 +17,7 @@
     license='MIT',
     python_requires='>=3.6',
     install_requires=['numpy',
+                      'Cython',
                       'scipy',
                       'pandas',
                       'pyyaml',