The purpose of the present study was to propose and test a model of work-family conflict based on Self-Determination Theory and the Hierarchical Model of Intrinsic and Extrinsic Motivation. The model posits that positive interpersonal factors both at work (i.e., one’s employer) and at home (e.g., one’s spouse) influence work and family motivation. Moreover, the model proposes that low levels of self-determined family and work motivation both contribute to family alienation, which in turn influences the experience of work-family conflict. Finally, work-family conflict leads to feelings of emotional exhaustion. Results from structural equation modeling supported the model. Although the model was supported for both men and women, some sex differences were uncovered at the mean level. Theoretical implications of the findings are discussed.