diff --git a/requirements_dev.txt b/requirements_dev.txt
index f3628529..de9f7cc4 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -10,7 +10,7 @@ Click>=7.0
 cocotb==1.8.0
 cookiecutter
 coverage
-cython==0.29.21
+cython==3.0.2
 femwell==0.1.8
 flake8
 gdsfactory==7.3.0  # Pinned for pydantic <v2 compatibility.
diff --git a/setup.py b/setup.py
index 87352b59..49312c2a 100644
--- a/setup.py
+++ b/setup.py
@@ -10,7 +10,7 @@
 requirements = [
     # "amaranth",  # Until they sort out their packaging issue, this dependency has to be installed separately. .
     "amaranth-yosys==0.25.0.0.post75",
-    "cython==0.29.21",
+    "cython==3.0.2",
     "jupytext==1.15.0",
     "Click>=7.0",
     "cocotb==1.8.0",