diff --git a/requirements.txt b/requirements.txt
index 019a23e68d..4827076649 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -54,7 +54,7 @@ marshmallow-sqlalchemy==0.8.1
 matplotlib==2.2.2
 mccabe==0.6.1
 mysql-connector==2.1.4
-nltk==3.2.2
+nltk==3.4.5
 numpy==1.14.2
 packaging==16.8
 paramiko==2.4.1