diff --git a/requirements.txt b/requirements.txt
index 99b61ab..89878de 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -99,7 +99,7 @@ munch==2.3.2
 nbconvert==5.4.0
 nbformat==4.4.0
 networkx==2.1
-nltk==3.3
+nltk==3.4.5
 nose==1.3.7
 notebook==5.6.0
 numba==0.39.0