diff --git a/requirements-benchmark.txt b/requirements-benchmark.txt
index 2012e49..7709e49 100644
--- a/requirements-benchmark.txt
+++ b/requirements-benchmark.txt
@@ -1,4 +1,4 @@
-nltk==3.5
+nltk==3.9
 spacy==2.1.8
 stanza==1.0.1
 syntok==1.3.1