There is provided a head-mounted display, a notification apparatus, a notification system, a notification method, and a program that allow a person not wearing a head-mounted display to know that a user still continues to wear a head-mounted display after a notification that a wearing time of the head-mounted display of this user has exceeded a predetermined time. A wearing time determination block determines a wearing time of the head-mounted display of the user. A notification block executes a first notification to the user if the wearing time has exceeded a first time and, when the wearing time has exceeded a second time longer than the first time, and executes a second notification to a person not wearing the head-mounted display.