diff --git a/requirements.txt b/requirements.txt
index 92d2d599..ca0d1e2b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@ matplotlib==2.2.4
 Django==1.11.29
 pandas==0.24.2
 scipy==1.2.2
-nltk==3.4.5
+nltk==3.6.6
 django_rest_swagger==2.2.0
 requests==2.22.0
 numpy==1.16.4