OBJECTIVE: To provide a comprehensive review of the literature regarding the role of external ankle support on joint kinematics, joint kinetics, sensorimotor function, and functional performance. DATA SOURCES: We searched MEDLINE and SPORT Discus databases from 1960-2001 for the key words ankle bracing, ankle support, ankle taping, and ankle prophylaxes. We also used personal libraries based on our own research to complement the existing literature. DATA SYNTHESIS: The effects of external ankle support have been studied on a plethora of dependent measures. Here, we specifically discuss the role of external ankle support on joint kinematics, joint kinetics, sensorimotor function, and functional performance and present a general consensus regarding the overall effects of these prophylactic devices. CONCLUSIONS/RECOMMENDATIONS: The effects of ankle support on joint kinematics during static joint assessment and on traditional functional-performance measures (ie, agility, sprint speed, vertical jump height) are well understood. However, the potential effects of ankle support on joint kinetics, joint kinematics during dynamic activity (eg, a cutting maneuver), and various sensorimotor measures are not well known. Future research investigating the role of external ankle bracing needs to focus on these areas.