A head-mounted display system includes a head-mounted display unit and a positioning and stabilising structure structured and arranged to hold the head-mounted display unit in an operational position over a user's face in use. The positioning and stabilising structure includes a rear support structure adapted to contact posterior regions of a user's head and at least one connector structured and arranged to interconnect the rear support structure to the head-mounted display unit. The rear support structure is in the form of a hoop comprising an occipital portion configured and arranged engage the user's head along a portion of the occipital bone adjacent a junction where the neck muscles attach to the occipital bone in use.