This chapter discusses about the psychological factors governing bioethics. Many models have been formulated to relate psychology and ethical decision-making. The important ones are discussed in this chapter. James Rest theoretical model to explain the ethical decision-making designed to elaborate on the various ethical behaviors and decisions in different perspectives. Moral sensitivity, moral judgment, moral motivation/intension, and moral character/action are the four different psychological processes. Thomas Johns formulated the model of moral intensity in 1991. Thomas Johns argued that moral intensity that is characteristic of moral issue influences ethical decision-making. Magnitude of consequences, temporal immediacy, social consensus, proximity, probability of effect, and concentration of effect are six dimensions of moral intensity. Steps of ethical decision-making are presented with the help of figure.