diff --git a/requirements.txt b/requirements.txt
index 7893ddc..cfe44a0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -32,7 +32,7 @@ mistune==0.8.4
 murmurhash==1.0.2
 nbconvert==5.5.0
 nbformat==4.4.0
-nltk==3.4.3
+nltk==3.4.5
 notebook==5.7.8
 numpy==1.16.3
 pandocfilters==1.4.2