diff --git a/requirements.txt b/requirements.txt
index 7d1aeba..44b54c9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -77,7 +77,7 @@ munch==2.1.1
 nbconvert==4.2.0
 nbformat==4.2.0
 networkx==1.11
-nltk==3.2.2
+nltk==3.4.5
 nose==1.3.7
 notebook==4.3.1
 numba==0.31.0