diff --git a/lib/requirements.txt b/lib/requirements.txt
index e952095ce..f83bf863e 100644
--- a/lib/requirements.txt
+++ b/lib/requirements.txt
@@ -46,7 +46,7 @@ matplotlib==3.0.0
 more-itertools==8.2.0
 murmurhash==1.0.2
 networkx==2.2
-nltk==3.4.5
+nltk==3.6.6
 numexpr==2.6.2
 numpy==1.18.1
 packaging==20.3