While recognition of the need for teacher education in media literacy is not new, in the context of social media it is growing. What this article offers is an approach to critical media literacy for teachers--what the authors call critical social literacy (CSL)--that treats media as a venue for the operation of power. By distinguishing between "power-over," "power-to," and "power-with", the authors explore how media engagement in the classroom can support teaching for social justice. Through media engagement, students can exercise their power to resist, challenge and transform media culture promoting exclusion and marginalization of social groups, while also recognizing extra-textual processes that sustain this culture.