diff --git a/requirements_rtd.txt b/requirements_rtd.txt
index a8d67b1..27b0e09 100644
--- a/requirements_rtd.txt
+++ b/requirements_rtd.txt
@@ -1,3 +1,4 @@
 sphinx>=1.2.0
 CommonMark>=0.5.6
 sphinx-argparse>=0.2.1
+jsonschema>=2.5.0