This paper attempts to further theoretical and empirical understanding of adherent and constituent mobilization by proposing and analyzing frame alignment as a conceptual bridge linking social psychological and resource mobilization views on movement participation. Extension of Goffinan's (1974) frame analytic perspective provides the conceptualltheoretical framework; field research on two religious movements, the peace movement, and several neighborhood movements provide the primary empirical base. Four frame alignment processes are identified and elaborated: frame bridging, frame amplification, frame extension, and frame transformation. The basic underlying premise is that frame alignment, of one variety or another, is a necessary condition for participation, whatever its nature or intensity, and that it is typically an interactional and ongoing accomplishment. The paper concludes with an elaboration of several sets of theoretical and research implications.