diff --git a/src/requirements.txt b/src/requirements.txt
index 89b5eb1..6efd352 100644
--- a/src/requirements.txt
+++ b/src/requirements.txt
@@ -3,7 +3,7 @@ bs4==0.0.1
 docutils==0.12
 facebook-sdk==1.0.0
 isodate==0.5.4
-nltk==3.2.1
+nltk==3.6.3
 numpy==1.11.0
 pandas==0.18.1
 python-dateutil==2.5.3
diff --git a/src/wordfreq_requirements.txt b/src/wordfreq_requirements.txt
index 3d98ed3..0d453e6 100644
--- a/src/wordfreq_requirements.txt
+++ b/src/wordfreq_requirements.txt
@@ -1,4 +1,4 @@
-nltk==3.2.1
+nltk==3.6.3
 numpy==1.11.0
 scikit-learn==0.17.1
 scipy==0.17.0