Emerging wearable technologies like head-mounted displays (e.g., Google Glass) and wrist-worn devices (e.g., Fitbit, Apple Watch 2.0) are always available, have the potential to provide quick access to information and offer relatively hands-free interaction compared to smartphones. Additionally, they can collect continuous health and fitness-related information of their wearer. For people with disabilities, these technologies may also offer possibilities of independent use. However, people with upper body motor impairments may not be able to gain from the potential benefits that these wearables can offer. For example, challenges related to performing multi-touch gestures and text entry, may magnify as the interaction space of some wearables gets even smaller. In my dissertation, I explore the potential impacts and assess the accessibility of existing mainstream wearable technologies, including head-mounted displays, smartwatches, and fitness trackers. Consequently, I implement and evaluate accessible wearable interactions for people with motor impairments for these wearables, specifically head-mounted displays and smartwatches.