diff --git a/DESCRIPTION b/DESCRIPTION
index d1063460..545ae82c 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -29,6 +29,7 @@ Suggests:
     pillar (>= 1.0.0),
     rmarkdown,
     spelling,
+    splines,
     testthat (>= 3.0.0),
     tibble (>= 1.1.0),
     vctrs (>= 0.3.0),