diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 275368b0ceeee8c0bd6b52458c18fb8d4192e2d0..88a2d4be414f2c8d1c6f90e80e03643345364169 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -19,6 +19,7 @@ before_script:
   # Install test dependencies
   - pip install -r requirements_test.txt
   - export PYTEST_QT_API=$QT_API
+  - export MPLBACKEND=qtagg
 
 .run-test:
   stage: test