diff --git a/requirements.txt b/requirements.txt
index a01419a..704dc07 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,7 +11,7 @@ grpcio==1.14.2
 html5lib==0.9999999
 idna==2.7
 Markdown==2.6.11
-nltk==3.3
+nltk==3.4.5
 numpy==1.14.5
 pkg-resources==0.0.0
 progress==1.4