An ankle foot orthosis includes a leg member, a foot member, and a drive member. The drive assembly includes a link member which may be hingedly secured to the foot member at a hinge location adjacent to the posterior end of the foot member. The drive assembly may be operable to selectively impart pivotal movement between the foot member and the link member about a first pivot axis, and pivotal movement between the foot member and the leg member about a second pivot axis at the hinge location. The leg member and the foot member strut may be selectively movable in a medial-lateral direction relative to a base of the foot member and the drive assembly. The inferior-superior location of the second pivot axis may be selectively adjustable for substantially aligning the second pivot axis with an axis of rotation of an ankle joint of the wearer.