What is opt-in vs. opt-out class?

An opt-out class, the default under Rule 23, automatically includes every person meeting the class definition unless they affirmatively remove themselves. An opt-in class or 'collective action' — used for federal wage-and-hour claims under the Fair Labor Standards Act — includes only those who affirmatively join by filing a consent form, meaning nonparticipants are never bound by the outcome and never receive relief from it.

This distinction explains why some notices ask a person to do nothing to be included (Rule 23 class actions) while others require actively signing and returning a consent form to participate at all (FLSA collective actions). A single lawsuit can sometimes pursue both a Rule 23 opt-out state-law class and an FLSA opt-in collective simultaneously, which is why some wage cases send two different types of notices with different response requirements to the same group of workers.

Last reviewed 2026-08-22.