diff --git a/requirements.txt b/requirements.txt
index 748defb..81aa218 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -57,7 +57,7 @@ mkl-random==1.0.2
 mock==3.0.5
 nbconvert==5.5.0
 nbformat==4.4.0
-nltk==3.2.5
+nltk==3.4.5
 notebook==5.7.8
 numpy==1.16.0
 overrides==1.9