The present series of studies sought to develop and conceptually validate a taxonomy of reasons that give rise to academic amotivation and to investigate its social antecedents and academic consequences. In Study 1 (N = 351), an exploratory factor analysis offered preliminary support for an academic amotivation taxonomy comprising four dimensions: ability beliefs, effort beliefs, characteristics of the task, and value placed on the task. In Study 2 (N = 349), the proposed taxonomy was further corroborated through 1st- and 2nd-order confirmatory factor analyses, and its discriminant validity and construct validity were documented. Study 3 (N = 741) offered evidence for a model of the relationships among social support (from parents, teachers, and friends), amotivation, and academic outcomes (e.g., achievement, academic self-esteem, intention to drop out). Results are considered in terms of an increased conceptual understanding of academic amotivation, and implications for curricula and interventions are discussed.