The concept of dehumanization lacks a systematic theoretical basis, and research that addresses it has yet to be integrated. Manifestations and theories of dehumanization are reviewed, and a new model is developed. Two forms of dehumanization are proposed, involving the denial to others of 2 distinct senses of humanness: characteristics that are uniquely human and those that constitute human nature. Denying uniquely human attributes to others represents them as animal-like, and denying human nature to others represents them as objects or automata. Cognitive underpinnings of the "animalistic" and "mechanistic" forms of dehumanization are proposed. An expanded sense of dehumanization emerges, in which the phenomenon is not unitary, is not restricted to the intergroup context, and does not occur only under conditions of conflict or extreme negative evaluation. Instead, dehumanization becomes an everyday social phenomenon, rooted in ordinary social-cognitive processes.