diff --git a/requirements.txt b/requirements.txt
index 2593862..07d51cf 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -30,7 +30,7 @@ Keras-Preprocessing==1.1.2
 Levenshtein==0.13.0
 Markdown==3.3.4
 mesh-tensorflow==0.1.19
-nltk==3.6.2
+nltk==3.9.4
 numpy==1.19.5
 oauthlib==3.1.1
 opt-einsum==3.3.0