diff --git a/requirements.txt b/requirements.txt
index f73e4d8..a590786 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -45,7 +45,7 @@ mkdocs-material-extensions==1.0.1
 mkdocs-rtd-dropdown==1.0.2
 mypy-extensions==0.4.3
 mysql-connector==2.2.9
-nltk==3.5
+nltk==3.6.6
 numpy==1.19.4
 packaging==20.8
 pandas==1.1.5