Drive for thinness is one of the major predictors of disordered eating behaviours. A wealth of research has identified various aspects of the culture of sport as risk factors for the development of drive for thinness. However, despite the consistency of these findings, drive for thinness in sport remains relatively under-researched. The purpose of this study was to examine the development of drive for thinness among females in sport. Semi-structured interviews were conducted with 37 competitive female athletes, aged 18 – 25, representing a variety of sports. Data were analyzed inductively using open, axial, and selective coding procedures. A model of the process by which females develop drive for thinness in sport is proposed, including six sequential stages of augmentation. Implications of these findings are discussed relative to prevention and best practice in sport.