This paper proposes a theoretical framework of moral and immoral development which considers not only reasoning, but also behavior and situational variables. Major theories of moral development proposed by Freud, Piaget, Kohlberg, Haan, and Hogan are used to illustrate the notion that, although empirical evidence shows that most individuals possess the potential for both moral and immoral expression, no theorist has been able to systematically incorporate the construct of immorality within his model. The components of the proposed model are discussed according to major structural components of earlier theories of moral development, and the way each moral type is identical to its equivalent immoral type with respect to reasoning and is the mirror-image of its equivalent immoral type with respect to action. Individual differences in development are explained by personality variables (socialization, empathy, autonomy), ego processes (coping, defending, fragmenting), and situational determinants. An assessment of the theory is discussed in terms of its applicability to actual rather than hypothetical moral dilemmas. (Author/NRB)