diff --git a/named-entity-disambiguation/requirements.txt b/named-entity-disambiguation/requirements.txt
index 76b8254..924be77 100644
--- a/named-entity-disambiguation/requirements.txt
+++ b/named-entity-disambiguation/requirements.txt
@@ -1,4 +1,4 @@
-nltk==3.4.5
+nltk==3.6.6
 numpy==1.15.4
 spacy==2.0.18
 https://github.com/explosion/spacy-models/releases/download/en_core_web_sm-2.0.0/en_core_web_sm-2.0.0.tar.gz#en_core_web_sm