diff --git a/tests/cli/test_cli.py b/tests/cli/test_cli.py
index 76a18789..e41bb021 100644
--- a/tests/cli/test_cli.py
+++ b/tests/cli/test_cli.py
@@ -9,6 +9,7 @@
 from contextlib import redirect_stdout
 from pathlib import Path
 
+import matplotlib as mpl
 import matplotlib.pyplot as plt
 import matplotlib.style
 import numpy as np
@@ -71,6 +72,9 @@ def setup_class(cls):
 
     @pytest.mark.parametrize("args", test_cases)
     def test_cli_results(self, args, capsys, inject_mocks, clean_plot):
+        # Use Ubuntu default backend for consistency across OS
+        mpl.use("agg")
+
         test = get_parser().parse_args(args)
         run(test)