diff --git a/pyproject.toml b/pyproject.toml
index 32634487..a84f9fba 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -277,6 +277,9 @@ markers = [
     "flaky: mark test as flaky",
 ]
 
+# Add filterwarnings to suppress the specific UserWarning
+filterwarnings = "ignore:.*custom validator is returning a value other than `self`.*:UserWarning"
+
 [tool.coverage.run]
 parallel = true
 branch = true