diff --git a/simptext/requirements.txt b/simptext/requirements.txt
index 8da5ca6..2b84e66 100644
--- a/simptext/requirements.txt
+++ b/simptext/requirements.txt
@@ -19,7 +19,7 @@ json2xlsx==1.3
 kenlm==0.0.0
 lxml==3.6.0
 MarkupSafe==0.23
-nltk==3.2.1
+nltk==3.4.5
 numpy==1.11.1
 openpyxl==2.3.5
 Pattern==2.6