This paper draws primarily on my own scholarship, supplemented by the limited academic resources available in the “peripheries” of the world where I live and work (namely, Somali society and Darfur, Sudan), to consider the relationship between colonialism and psychology. I first consider the history of psychology in justifying and bolstering oppression and colonialism. I then consider the ongoing intersection of colonialism and psychology in the form of metacolonialism (or coloniality). I end with thoughts about decolonizing psychological science in teaching, social, and clinical practice. To decolonize psychological science, it is necessary to transform its focus from promotion of individual happiness to cultivation of collective well-being, from a concern with instinct to promotion of human needs, from prescriptions for adjustment to affordances for empowerment, from treatment of passive victims to creation of self-determining actors, and from globalizing, top-down approaches to context-sensitive, bottom-up approaches. Only then will the field realize its potential to advance Frantz Fanon’s call for humane and just social order.