This chapter points out relations between action theory and social psychology. An expectancy-value analysis of the Milgram experiment suggests that subjects calculated obedience as the most desirable action given their values. Exchange theory suggests that actors must not only keep track of their options, but must also keep track of the options of the people with whom they are interacting. Action theory has striking implications for the “person-perception” literature. The effective force behind social movements is a shared understanding of the social situation. The skills and shared understandings needed for collective action may have to be developed over time; for example, many successful revolutions and social movements have been “practiced”. Action theory’s ability to handle different, but objective, representations of the same situation has implications for the personality-situation controversy. Action theory can allow people to have different understandings of the same situation without resorting, at least immediately, to tautology.