There's an established pattern for this, which is to provide users with a choice of: Sort order: - By First Name - By Last Name Display order:

There's an established pattern for this, which is to provide users with a choice of: Sort order: - By First Name - By Last Name Display order: - First, Last - Last, First Obviously, users can input names in a multitude of ways. But the convention is to offer at least two distinct fields, "First name" and "Last name". The sort order determines if the items are ordered by first name or last name. And the display order determines if the full name for each item is displayed as First name and then or last name, or the other way around. And finally, set a default based by the user's locale and region.