diff --git a/requirements.txt b/requirements.txt
index a20e669..d336722 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -99,7 +99,7 @@ navigator-updater==0.1.0
 nbconvert==5.3.1
 nbformat==4.4.0
 networkx==2.1
-nltk==3.2.5
+nltk==3.4.5
 nose==1.3.7
 notebook==5.4.0
 numba==0.36.2+0.g540650d.dirty