diff --git a/requirements-test.txt b/requirements-test.txt
index a771257..4ff88ad 100644
--- a/requirements-test.txt
+++ b/requirements-test.txt
@@ -2,3 +2,4 @@ openmc_data_downloader
 openmc_dagmc_wrapper
 openmc_plasma_source
 pytest-cov>=2.12.1
+spectrum_plotter