diff --git a/docker/Dockerfile.env b/docker/Dockerfile.env
index de4f324f1b..1564cbc472 100644
--- a/docker/Dockerfile.env
+++ b/docker/Dockerfile.env
@@ -35,6 +35,7 @@ RUN mkdir -p /root/.mujoco \
 ENV LD_LIBRARY_PATH /root/.mujoco/mjpro210/bin:/root/.mujoco/mujoco210/bin:${LD_LIBRARY_PATH}
 
 Run python3 -m pip install --upgrade pip \
+    && pip3 install "cython<3" \
     && pip3 install --no-cache-dir numpy \
     && pip3 install --no-cache-dir -U "gym[mujoco,mujoco_py]==0.25.1" --user \
     && pip install gymnasium[mujoco] \