diff --git a/README.rst b/README.rst
index d429ea4..1aef0bd 100644
--- a/README.rst
+++ b/README.rst
@@ -25,7 +25,7 @@ Requirements:
   https://doc.sagemath.org/html/en/reference/spkg/pari#spkg-pari
   for availability in distributions (GNU/Linux, conda-forge, Homebrew, FreeBSD),
   or install from source.
-- Python >= 3.6
+- Python >= 3.9
 - pip
 
 Install cypari2 via the Python Package Index (PyPI) via
diff --git a/pyproject.toml b/pyproject.toml
index be9d05b..224d5d1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -17,6 +17,7 @@ authors = [
 dependencies = [
     "cysignals>=1.7",
 ]
+requires-python = ">=3.9"
 readme = "README.rst"
 license = {text = "GNU General Public License, version 2 or later"}
 keywords = ["PARI/GP number theory"]