diff --git a/requirements.txt b/requirements.txt
index 4a0e6f3..b640f37 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -26,7 +26,7 @@ matplotlib==2.1.0
 msgpack-numpy==0.4.1
 msgpack-python==0.5.2
 murmurhash==0.28.0
-nltk==3.2.5
+nltk==3.4.5
 numpy==1.14.0
 pandas==0.20.3
 pandoc==1.0.2