This chapter traces the historical roots of social justice in counseling psychology and reviews social justice in counseling psychology practice, training, and research. Social justice advocacy in counseling psychology urges counseling psychologists to use their knowledge and expertise to actively create new opportunities for clients, to change the systems that perpetuate injustice, and to advocate for new policies that will institutionalize equity and fairness. We also identify the challenges and barriers to conducting social justice work, and we highlight some of the ethical issues and dilemmas of social justice work. Finally, we make some recommendations for policy and legislation, and suggest next steps for counseling psychologists to be social justice agents.