diff --git a/pyproject.toml b/pyproject.toml
index 928f5746..a6b8bd48 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,3 +1,6 @@
+[build-system]
+requires = ["cython"]
+
 [tool.black]
 line-length = 101
 include = '\.pyi?$'
diff --git a/requirements.txt b/requirements.txt
index 8eb5511e..97fd1040 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,6 @@ ray[rllib]==0.8.5
 pettingzoo>=1.18.1
 opencv-python>=3.4
 numpy>=1.21.0
-cython>=0.29
 scipy
 pandas
 matplotlib