diff --git a/appveyor.yml b/appveyor.yml
index d72d295..2578e04 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -11,6 +11,7 @@ environment:
     - PYTHON: "C:\\Python36-x64"
 
 install:
+  - "git submodule update --init --recursive"
   - "%PYTHON%\\python.exe -m pip install -U pip wheel nose cython"
 
 build: off