diff --git a/requirements.txt b/requirements.txt
index 040ba6c..a3be3fc 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,7 +4,7 @@ cython==0.29.1
 evalai==1.3.0
 h5py==2.8.0
 mypy_extensions==0.4.1
-nltk==3.4.3
+nltk==3.6.6
 numpy==1.15.4
 pillow==6.2.0
 tb-nightly