How do teachers account for homework-related inequalities? Our longitudinal ethnographic study reveals that, despite awareness of structural inequalities in their students' lives, elementary- and middle-school teachers' practices centered the myth of meritocracy. They treat struggles with math homework as products of students' and (particularly in elementary grades) parents' insufficient responsibility, effort, and motivation. These interpretations then justify homework practices that reinforce inequalities, including assigning homework that exceeds what students can complete independently and rewarding/punishing students based on homework. We discuss implications for debates about homework and the dangers of meritocracy myths and offer recommendations for more equitable alternatives.