diff --git a/.ci/requirements.txt b/.ci/requirements.txt
index bda64bf..83d5def 100644
--- a/.ci/requirements.txt
+++ b/.ci/requirements.txt
@@ -1,4 +1,4 @@
-cython==0.24.1
+cython==0.25.2
 aiohttp
 tinys3
 twine
diff --git a/requirements.dev.txt b/requirements.dev.txt
index bb34904..98904b6 100644
--- a/requirements.dev.txt
+++ b/requirements.dev.txt
@@ -1,2 +1,2 @@
-Cython==0.24.1
+Cython==0.25.2
 Sphinx>=1.4.1