diff --git a/moose-core/tests/python/test_muparser.py b/moose-core/tests/python/test_muparser.py
index 447f589b4a497d0b1869ef6b0ad3fdb9ca6dee37..205479f44a1726fe88f128d86f74c132b75c168a 100644
--- a/moose-core/tests/python/test_muparser.py
+++ b/moose-core/tests/python/test_muparser.py
@@ -7,6 +7,8 @@ Modified from https://elifesciences.org/articles/25827 , Fig4.py
 """
 import sys
 import os
+import matplotlib
+matplotlib.use( 'Agg' )
 import numpy as np
 import sys
 import numpy as np