diff --git a/requirements.txt b/requirements.txt
index 8003e78..3e4965c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -27,7 +27,7 @@ jedi==0.13.1
 lazy-object-proxy==1.4.3
 mccabe==0.6.1
 mysqlclient==1.4.6
-nltk==3.4.5
+nltk==3.6.6
 numpy==1.14.4
 openpyxl==2.5.4
 parso==0.3.1