diff --git a/requirements.txt b/requirements.txt
index 37c4339..27be9f4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,7 +4,7 @@ Flask==1.1.2
 
 mlflow==1.23.1
 
-nltk==3.5
+nltk==3.6.6
 notebook==6.4.1
 
 numpy==1.18.4