This chapter is concerned with the use of wearable devices for disabled and extreme sports. These sporting disciplines offer unique challenges for sports scientists and engineers. Disabled athletes often rely on and utilize more specialist equipment than able-bodied athletes. Wearable devices could be particularly useful for monitoring athlete-equipment interactions in disability sport, with a view to improving comfort and performance, while increasing accessibility and reducing injury risks. Equipment also tends to be key for so called “extreme” sports, such as skiing, snowboarding, mountain biking, bicycle motocross, rock climbing, surfing, and white-water kayaking. These sports are often practiced outdoors in remote and challenging environments, with athletes placing heavy demands on themselves and their equipment. Extreme sports also encompass disability sports, like sit skiing and adaptive mountain biking, and the popularity and diversity of such activities is likely to increase with improvements in technology and training, as well as with the support of organizations like the High Fives Foundation (highfivesfoundation.org) and Disability Snowsport, United Kingdom (disabilitysnowsport.org.uk). Within this chapter in these two sporting contexts, wearable devices are broadly associated with those that can be used to monitor the kinetics and kinematics of an athlete and their equipment. This chapter will first consider image-based alternatives and then focus on wearable sensors, in three main sections covering, (1) sports wearables, (2) disability sport and the use of wearables, and (3) extreme sport and the use of wearables, as well as making recommendations for the future.