diff --git a/requirements.txt b/requirements.txt
index 0b6c4d0..12d8d5d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -77,7 +77,7 @@ multidict==4.5.2
 Naked==0.1.31
 nbconvert==5.4.1
 nbformat==4.4.0
-nltk==3.4
+nltk==3.6.3
 notebook==5.7.8
 numpy==1.16.2
 opencv-contrib-python==3.4.2.17