diff --git a/requirements.txt b/requirements.txt
index 4a9901e..af605c1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 editdistance==0.4
 Lemmagen==1.2.0
-nltk==3.2.5
+nltk==3.9
 numpy==1.14.0
 scipy==1.0.0
 pandas==0.22.0