An oral care implement handle or a refill head therefor. The oral care implement handle may include a gripping portion and a stem protruding from a shoulder of the gripping portion. The stem may include a post located at a distal end of the stem. The post may have a non-circular transverse profile. More specifically, the post may include a hub portion and a protuberance that either protrudes radially from a side surface of the hub portion, protrudes upward from the shoulder of the gripping portion, or both. The refill head may include a sleeve having an inner surface that defines an internal cavity. The internal cavity may include a central portion and at least one slot portion extending radially from the central portion. Thus, the internal cavity of the sleeve portion may have a profile configured to receive the stem of the oral care implement handle.
