The adoption of Augmented Reality (AR) technology has increased over the years. AR enhances various activities for consumers and businesses, particularly in industrial contexts. The threedimensional virtual experience is realized by the usage of Head-Mounted Displays (HMD). These devices provide access to sensitive data and services. Thus, secure and usable authentication schemes are essential to control access to the HMD and the stored data as well as schemes to authenticate to the services one wants to use with the AR device.We conducted a systematic literature review on knowledge-based authentication schemes for AR HMD. 31 different schemes were identified. These schemes were assessed regarding various aspects including the type of AR HMD, the type of secret, howusers input their secret, aswell as usability and security aspects. We discuss gaps for future work.