Many girls and boys quit sport in their teens. The reasons for this have eluded scientists and sports organizations for many years. The aim of this study was to understand why girls quit sport and to increase knowledge about what sport clubs can do to prevent girls from dropping out from floorball. Particular focus was directed towards the disengagement process which girls undergo when making the decision to quit their sport participation. The study draws on Ebaughs (1988) sociological theory of the disengagement process and is based on data from 24 semi-structured interviews with 12 girls aged 13-18 years (n=12) and with one parent of each of the girls (n=12). The results show that the disengagement process can take from a few months up to two years before the girl takes the final decision. Six factors were identified as the main reasons for the girls to quit their sport with the results indicating that a combination of three to four factors are involved. The most salient factors were an increased focus on sport performance and results, changes in the team's formation, new coaches and changes in the coach's attitudes, interest in other activities or sports, lack of time and high demands on themselves. The results indicate that changes within the sport were critical to the girls’ decision. Overall, the research contributes to a deeper understanding of the disengagement process and the reasons for girls dropping out of sports in their teenage years.