diff --git a/testing/config/marionette_harness_test_requirements.txt b/testing/config/marionette_harness_test_requirements.txt
index db08046fee..0ca302856f 100644
--- a/testing/config/marionette_harness_test_requirements.txt
+++ b/testing/config/marionette_harness_test_requirements.txt
@@ -8,6 +8,6 @@
 ../marionette/harness
 
 # pytest
-py==1.4.31
+py==1.10.0
 pytest==2.9.1
 ../../python/mock-1.0.0