diff --git a/requirements.txt b/requirements.txt
index a2c19ad..c636959 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -76,7 +76,7 @@ nbconvert==5.2.1
 nbformat==4.4.0
 neo4j-doc-manager==1.0.0.dev11
 neo4jrestclient==2.1.1
-nltk==3.2.4
+nltk==3.4.5
 notebook==5.0.0
 numexpr==2.6.2
 numpy==1.13.1