diff --git a/requirements.txt b/requirements.txt
index 1dd131c..5a1a748 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -25,7 +25,7 @@ jsonschema==2.6.0
 klein==17.2.0
 matplotlib==2.0.2
 mitie==0.2.0
-nltk==3.2.5
+nltk==3.4.5
 numpy==1.13.3
 pandas==0.16.0
 pathlib==1.0.1