diff --git a/install/gargamelle/requirements.txt b/install/gargamelle/requirements.txt
index 8bc4a94e..7393e3bc 100644
--- a/install/gargamelle/requirements.txt
+++ b/install/gargamelle/requirements.txt
@@ -17,7 +17,7 @@ python-igraph>=0.7.1
 jdatetime==1.7.2
 kombu==3.0.37                  # messaging
 langdetect==1.0.6              #detectinglanguage
-nltk==3.1
+nltk==3.4.5
 numpy==1.13.1
 psycopg2==2.6.2
 pycountry==1.20