diff --git a/requirements/base.txt b/requirements/base.txt
index 760c742..4815296 100644
--- a/requirements/base.txt
+++ b/requirements/base.txt
@@ -38,7 +38,7 @@ scikit-learn==0.23.2
 lightgbm==2.3.1
 xlrd==1.2.0
 tabulate==0.8.7
-nltk==3.5
+nltk==3.9
 
 # Django
 Django==3.1.6