A functional electrical stimulation (FES) orthosis for FES to a limb segment, including: (a) a semi-rigid, self-retaining C-shaped frame, the frame configured to substantially envelop the limb segment, the frame including a first flexible and elongated circumferentially retaining element and at least a first and a second opposing flexible and elongated circumferentially retaining elements disposed on the circumferentially opposite side of the frame, the first retaining element and the first opposing retaining element forming a pair of opposing retaining elements, and (b) a surface electrical stimulation electrode for contacting at least one stimulation point on a surface of the limb segment, associated with, and supported by, the frame, the surface electrode for electrically associating, via the frame, with a neuroprosthetic stimulator unit, so as to provide FES, wherein the opposing retaining elements are configured to be radially spring-loaded towards a center of the frame, such that in donning the orthosis around the limb segment, the limb segment applies a counter-pressure from within the frame, against the opposing retaining elements, such that the orthosis is firmly and fixedly self-retained in a pre-determined position on the surface.