The nature of the relevance and relation of Wittgenstein's philosophy to psychology is examined in this chapter starting with general issues surrounding the relations between philosophy and science, and highlighting misleading pictures and comparisons identified by Wittgenstein in relation to psychology's supposed status, unlike physics, as a "young science". A Wittgensteinian perspective is developed about pernicious and positive forms of reflexivity, respectively, arguing that Wittgenstein's later philosophy is not postmodern or self-referentially inconsistent and showing that psychology can be fruitfully compared with mathematics. The game analogy of psychology is used to avoid the problems of constructing metatheories about social and psychological science, clarify the role of theoretical psychology, and outline the importance of achieving a surview of the grammar of psychological and metapsychological concepts.