The present study tests the theories of reasoned action and planned behavior in the context of women's participation in collective action. Participants were 387 women who completed two questionnaires with an interval of 1 year. In the first questionnaire, participants were asked to provide measures of attitudinal, normative, and control factors, as well as measures of intention to participate in 4 group-related activities over the coming year. One year later in the second questionnaire, the same women provided measures of the degree to which they had actually participated in these behaviors during the course of the year. Findings showed strong relationships between attitudinal factors and intentions, and between intentions and behavior. The addition of perceived behavioral control, as specified by the theory of planned behavior, made little difference in regression analyses. Further analyses focused on the mediating role of identification as an activist. This revealed that attitudinal considerations were only important in the prediction of intention for those individuals with a weaker sense of themselves as activists. It is suggested that expectancy-value calculations may be less important in predicting the intentions of strongly committed individuals to engage in group-relevant acts.