Corporations increasingly pay attention to issues of social responsibility, but their policies and procedures to articulate such responsibilities are not just a result of the good will of top management. Often, such policies and procedures are devised because some stakeholders raised their voice on issues relating to the interests of employees, investors, governments, and others. One category of visible though heterogeneous stakeholders is composed of "activist groups." This article presents four types of tactics that activist groups use to leverage pressure on firms and that do not rely on the state or legal action for resolution of the issue: shareholder activism, political consumerism, social alliances, and alternative business systems. The article concludes with some corporate policy responses to these tactics, illustrated with some examples.