diff --git a/requirements.txt b/requirements.txt
index a073000..9a65c5b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,6 +4,6 @@ gunicorn==19.9.0
 itsdangerous==1.1.0
 Jinja2==2.10
 MarkupSafe==1.1.0
-nltk==3.3
+nltk==3.4.5
 six==1.11.0
 Werkzeug==0.14.1