This dissertation examines the activities and texts of four groups of activists who use culture jamming as a tactic to challenge dominant ideologies as they advocate for progressive social, cultural and economic change. Culture jamming, as defined here, is a practice whereby texts critical of the status quo are created through the appropriation and/or mimicry of the aesthetics and/or language that are a part of popular, or at least widely experienced, culture. Exploring the work of the Yes Men, the Adbusters Media Foundation, the Billboard Liberation Front and the Illegal Art exhibit, I argue that through their culture jamming these activists take critical theory into practice as a part of their goal is to raise the critical consciousness of the public. Confronting the issues of globalization, consumerism, and the political economy of the media in the United States, these culture jammers aim to highlight aspects of domination and oppression in their view results primarily from the corporate control of culture and politics. Using theories of ideology and hegemony developed by Karl Marx, Antonio Gramsci, Stuart Hall, and Raymond Williams to guide my analysis, I trace how each of these groups develop, present, and promote their critique. I steer clear of discussing the effectiveness of these culture jammers, focusing instead on the actions they take and theorizing some of the possible challenges and limitations they face in light of their own experiences. Differing requirements of cultural capital and deeper contextual information for most, if not all, of these culture jamming activities can make them especially complex forms of activism. What becomes clear is that culture jamming may be a tactic best suited to the maintenance of an activist community of people who already hold a critical position, as the jammer’s challenges to dominant culture and ideologies can be lost because of the form of the critique, or marginalized or otherwise ignored by the mainstream media. / text