diff --git a/requirements.txt b/requirements.txt
index d19e293..7cb8f20 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -80,7 +80,7 @@ lxml==4.2.1
 Markdown==2.6.11
 MarkupSafe==1.0
 matplotlib==2.1.2
-nltk==3.2.5
+nltk==3.4.5
 numpy==1.14.3
 oauth2client==3.0.0
 oauthlib==2.0.6