diff --git a/setup.py b/setup.py
index 0440a3d42ca44861d0991a67be3da8d84523a674..4a2d527811c49b4e98af853a1a0eec947744742d 100644
--- a/setup.py
+++ b/setup.py
@@ -23,7 +23,7 @@ setup(
     long_description_content_type='text/markdown',
     name='lektor-pythonmarkdown',
     py_modules=['lektor_pythonmarkdown'],
-    install_requires=['markdown'],
+    install_requires=['markdown<3.0.0'],
     tests_require=['lektor'],
     setup_requires=['setuptools_scm'],
     use_scm_version=True,