An orthotic device for footwear (10, Fig 1) comprises a substantially planar body having a resiliently deformable outer peripheral portion (12, Fig 1) and an inner array of detachably couplable cells 22. Each cell has coupling means (e.g. one or more protuberances 26 and recesses 28) which permits it to detachably couple to other cells and with the outer peripheral portion. The cells are orientated such that an interface between neighbouring cells extends non-parallel with the longitudinal axis and lateral axis of the footwear. The cells may have a plurality of cell faces and may be hexagonal in shape.
