diff --git a/gstlal-calibration/python/calibhandler.py b/gstlal-calibration/python/calibhandler.py
index 1ce41e8f612d6c19c74c646821c43b5058411dc3..5c5aaa16d100010962a6d4becb82b4170db289ee 100644
--- a/gstlal-calibration/python/calibhandler.py
+++ b/gstlal-calibration/python/calibhandler.py
@@ -25,6 +25,7 @@
 import numpy
 import StringIO
 import threading
+import json
 
 import gi
 gi.require_version('Gst', '1.0')