BACKGROUND: Ankle injury is the most common injury in men's and women's basketball, regardless of the level of competition. PURPOSE: To use the National Collegiate Athletic Association (NCAA) Injury Surveillance Program/System (ISP/ISS) to review the 10-year epidemiology of ankle injuries in men's and women's collegiate basketball players. STUDY DESIGN: Descriptive epidemiology study. METHODS: The NCAA ISP was queried for men's and women's collegiate basketball ankle injury data from the 2004 through 2014 academic years. Ankle injury rates were calculated based on injuries per athlete-exposure (AE). Injury proportion ratios (IPRs) were determined by comparing variables between sexes. Activity and position of injury were also studied. RESULTS: Over the 10-year study period, most ankle injuries in collegiate basketball occurred in the preseason (female, 1.45/1000 AEs; male, 2.00/1000 AEs), were contact related (female, 50.4%; male, 57.6%), were treated conservatively (female, 98.5%; male, 99.3%), and were new injuries (female, 78.0%; male, 78.9%), resulting in a time loss of less than 7 days (female, 62.7%; male, 65.2%). The most common injury types were lateral ligament complex tears (female, 83.5%; male, 80.0%), deltoid ligament tears (female, 5.6%; male, 7.2%), and high ankle sprains (female, 7.1%; male, 7.0%). Guards experienced the highest rate of ankle injuries in competition (female, 50.1%; male, 43.3%), and rebounding was found to be the most common activity during an injury (female, 30.3%; male, 34.4%). The rate of ankle injuries was significantly lower in women than in men (IPR, 0.81 [95% CI, 0.75-0.88]). CONCLUSION: This study found that most ankle injuries in collegiate basketball occurred during the preseason, were contact related, were treated conservatively, and were new injuries that resulted in a time loss of less than 7 days.