diff --git a/requirements.txt b/requirements.txt
index bc09bc1..7c164f3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -33,7 +33,7 @@ matplotlib==3.0.2
 mistune==0.8.4
 nbconvert==5.4.0
 nbformat==4.4.0
-nltk==3.4
+nltk==3.4.5
 notebook==5.7.4
 numpy==1.15.4
 opencv-python==3.4.5.20