diff --git a/requirements.txt b/requirements.txt
index 5a0517d..38c96eb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,7 +10,7 @@ codecov==2.0.5
 # NLP
 numpy==1.13.3
 PyYAML==3.12
-nltk==3.2.5
+nltk==3.4.5
 scikit-learn==0.19.1
 scipy==1.0.0
 pyxdameraulevenshtein