This study examines the impact of group identification and social context on willingness to participate in industrial protest. Trade union members (N = 313) completed a survey indicating their willingness to participate in union activities, their perceptions of the union and its role, and their attitudes toward present and former governments. Three independent conditions defined the union and its activities in different ways: either (a) referring to conflict with the present government, (b) referring to this conflict together with the government's threat to the union, or (c) presenting no additional information (a control condition). Results indicated that participants who identified highly with the union were more willing to participate in collective action to the extent that issues were defined in conflictual terms. Low identifiers resiled from participation in union activities when reference was made to conflict alone, but this effect was attenuated when reference was also made to threat. Results suggest that collective action is not simply a product of identification, but is also shaped by the distinct meaning which such action assumes for high and low identifiers within a given context.