diff --git a/requirements.txt b/requirements.txt
index 2285278..0ca3c37 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 gensim==3.0.0
-nltk==3.4.5
+nltk==3.6.6
 numpy==1.12.1
 Pillow==6.2.0
 progressbar2==3.34.3