diff --git a/requirements.txt b/requirements.txt
index 246b925..52188b3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -18,7 +18,7 @@ jsonschema==2.6.0
 kiwisolver==1.0.1
 MarkupSafe==1.0
 matplotlib==2.2.2
-nltk==3.3
+nltk==3.4.5
 numpy==1.14.5
 oauthlib==2.1.0
 pandas==0.23.3