diff --git a/lib/galaxy/tool_util/linters/inputs.py b/lib/galaxy/tool_util/linters/inputs.py
index 437efe5e76f..78de207632b 100644
--- a/lib/galaxy/tool_util/linters/inputs.py
+++ b/lib/galaxy/tool_util/linters/inputs.py
@@ -163,8 +163,6 @@ def lint_inputs(tool_xml, lint_ctx):
                 lint_ctx.error(f"Parameter [{param_name}]: expression validator without content")
             if vtype != "expression" and validator.text is not None:
                 lint_ctx.warn(f"Parameter [{param_name}]: '{vtype}' validators are not expected to contain text (found '{validator.text}')")
-            if vtype == "regex" and "expression" not in validator.attrib:
-                lint_ctx.error(f"Parameter [{param_name}]: '{vtype}' validators need to define an 'expression' attribute")
             if vtype in ["in_range", "length", "dataset_metadata_in_range"] and ("min" not in validator.attrib or "max" not in validator.attrib):
                 lint_ctx.error(f"Parameter [{param_name}]: '{vtype}' validators need to define the 'min' or 'max' attribute(s)")
             if vtype in ["metadata"] and ("check" not in validator.attrib or "skip" not in validator.attrib):