diff --git a/requirements.txt b/requirements.txt
index 3037d1d..f5d702e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -204,7 +204,7 @@ nav-msgs==4.2.4
 netaddr==0.8.0
 netifaces==0.11.0
 networkx==3.4
-nltk==3.9.1
+nltk==3.9.4
 nose==1.3.7
 nose2==0.9.2
 notify2==0.3