After describing limitations of the assumption of rational self-interest, which has dominated considerable theory in the social and behavioral sciences, I advance six propositions relevant to our understanding of interpersonal orientations. Based on empirical research, as well as principles of interdependence theory, it is argued that the power of individualistic orientation, while important, tends to be overestimated (Proposition 1), and that this orientation needs to be complemented by the orientations of cooperation (enhancement of joint outcomes), egalitarianism (enhancement of equality in outcomes), generosity (enhancement of other's outcomes), and competition (enhancement of relative advantage over other's outcomes) (Proposition 2). Three further propositions focus on the inter-relatedness of prosocial orientations (Proposition 3), the social development of prosocial orientation (Propositions 4 and 5), and situational and dispositional views of interpersonal orientations (Proposition 6). Evidence in support of these propositions, especially the latter three propositions, is evaluated by classic and/or recent research. I close by outlining four lines of research that are important for understanding the implications of the propositions discussed in this chapter.