diff --git a/requirements-pypy-dev.txt b/requirements-pypy-dev.txt
index c2177e8f..9b1bd132 100644
--- a/requirements-pypy-dev.txt
+++ b/requirements-pypy-dev.txt
@@ -1 +1 @@
-tornado==4.5.3
+tornado==6.3.3
diff --git a/requirements27-dev.txt b/requirements27-dev.txt
index 6f61555f..33b51548 100644
--- a/requirements27-dev.txt
+++ b/requirements27-dev.txt
@@ -1,3 +1,3 @@
-tornado==4.5.3
+tornado==6.3.3
 twisted
 pyopenssl
diff --git a/requirements33-dev.txt b/requirements33-dev.txt
index c2177e8f..9b1bd132 100644
--- a/requirements33-dev.txt
+++ b/requirements33-dev.txt
@@ -1 +1 @@
-tornado==4.5.3
+tornado==6.3.3
diff --git a/requirements34-dev.txt b/requirements34-dev.txt
index b816915b..0ea6d02d 100644
--- a/requirements34-dev.txt
+++ b/requirements34-dev.txt
@@ -1,4 +1,4 @@
 pytest-asyncio==0.5.0
-tornado==4.5.3
+tornado==6.3.3
 aiohttp==2.3.10
 typing==3.6.4
diff --git a/requirements35-dev.txt b/requirements35-dev.txt
index 5dda7e18..a32afd3d 100644
--- a/requirements35-dev.txt
+++ b/requirements35-dev.txt
@@ -1,3 +1,3 @@
 pytest-asyncio
-tornado==4.5.3
+tornado==6.3.3
 aiohttp==2.3.10
diff --git a/requirements36-dev.txt b/requirements36-dev.txt
index 5dda7e18..a32afd3d 100644
--- a/requirements36-dev.txt
+++ b/requirements36-dev.txt
@@ -1,3 +1,3 @@
 pytest-asyncio
-tornado==4.5.3
+tornado==6.3.3
 aiohttp==2.3.10