This article identifies and examines the processes through which the social justice movements of African Americans in the US, Oromos in Ethiopia, and Southern and Western Sudanese in Sudan emerged, and the successes and failures of these movements in a global and comparative perspective. It specifically explores four interrelated issues. First, the paper deals with some theoretical and methodological insights. Second, the piece explains how the racialized capitalist world system and its political structures facilitated the creation of the states of the US, Ethiopia, and Sudan and legalized racial/ethnonational oppression, colonialism, exploitation, and continued subjugation. Third, it explains comparatively the processes, developments, objectives, and outcomes of these movements. Finally, the paper explores issues of social justice as the promotion of the principle of political self-determination and democratic and human rights under the rule of law.