The purpose of this literature review was to examine the current studies identifying sport specialization of collegiate athletes. Four aspects of specialization were identified: (1) age of sport initiation, (2) age of sport specialization, (3) differences of specialization between team-based and individual-based sports, and (4) reason for sport specialization. Key terms were searched in three databases between the years 2000-2020. Relevant articles were screened using inclusion and exclusion criteria. Six studies were eligible for review. The age of sport initiation ranged from four to nine years old. All but one investigation identified sport specialization older than twelve years old, classifying only one group of subjects as early sport specializers. Individual sport athletes specialized at a younger age than team sport athletes did. Finally, the most common reason for specialization was the love of the sport and the desire to improve.