diff --git a/requirements.txt b/requirements.txt
index 723f0ba..e84a2e9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,7 +6,7 @@ scikit-learn==0.20.1
 pandas==0.25.1
 torch==1.0.1.post2
 tqdm==4.36.1
-nltk==3.4.5
+nltk==3.6.6
 xgboost==0.90
 spacy==2.0.18
 boto3==1.9.111