A receiver pin lock for insertion into first and second sized opposed engaging apertures of first and second hitch receivers is shown and described. The receiver pin lock may include a stem, a first stepped portion extend from the stem, and a lock member selectively engageable with the stem, the lock member preventing removal of stem from either of the first and second hitch receivers. The receiver pin lock may also include a second stepped portion positioned on the lock member and extending from the stem, where the stem is configured to operatively engage the first sized engaging apertures of the first hitch receiver and the first and second stepped portions are configured to operatively engage the second sized engaging apertures of the second hitch receiver.