diff --git a/devtools/dev.yml b/devtools/dev.yml
index 033f9a1..6df7da7 100644
--- a/devtools/dev.yml
+++ b/devtools/dev.yml
@@ -6,7 +6,7 @@ dependencies:
   # Base depends
   - python
   - numpy
-  - cython
+  - cython=3.0.0
   - scipy
   # docs
   - mock