diff --git a/requirements.txt b/requirements.txt
index c3b85f2..7d172b1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -77,7 +77,7 @@ multipledispatch==0.4.9
 nbconvert==4.2.0
 nbformat==4.2.0
 networkx==1.11
-nltk==3.2.4
+nltk==3.4.5
 nose==1.3.7
 notebook==5.4.1
 numpy==1.12.1