diff --git a/requirements.txt b/requirements.txt
index b01ad15..f2e05ff 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -50,7 +50,7 @@ mistune==0.8.4
 nbconvert==5.4.0
 nbformat==4.4.0
 networkx==2.2
-nltk==3.4
+nltk==3.4.5
 notebook==5.7.0
 numpy==1.14.5
 olefile==0.46