This literature review looks at the history of Critical Theory - from its roots in European neo-Marxism, through its evolution in American academia into identitarianism - to its adoption by the Canadian province of Ontario as the hegemonic theory guiding K-12 education. Rarely subjected to criticism in Canadian educational scholarship, this literature review provides an in-depth look at both theoretical and evidence-based criticisms of a Critical Theory of Education from American and British scholars, particularly with respect to how it has crowded out learning science in guiding curricular and pedagogical choices made by the Ministry of Education, thereby harming the very students it claims to advocate for. The discussion following the literature review considers the suitability of a Critical Theory-based public education system, given its hostility to the liberalism upon which Canada was founded, and which serves as a unifying principle aiding social cohesion in a nation made up of disparate cultures. Given Critical Theory’s divisiveness and interest in dismantling society, it is hoped that this literature review sparks interest among policy-makers, educators, parents, and the general public to question and challenge Critical Theory’s capture of K-12 education, for the sake of equitably preparing all children – no matter their background – for participation in adult life.