diff --git a/requirements.txt b/requirements.txt
index 0d61a6b..45bcd9c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 Distance==0.1.3
-nltk==3.4.5
+nltk==3.6.6
 numpy==1.17.2
 Pillow==6.1.0
 pkg-resources==0.0.0