diff --git a/requirements.txt b/requirements.txt
index 9f70074..3c1f6e6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 scipy==1.10.0
-nltk==3.4.5
+nltk==3.6.6
 lockfile==0.12.2
 pandas==0.23.4
 matplotlib==2.2.3