Abstract: A wheelchair has lateral frames each constituted by a prefabricated modular front frame unit and a prefabricated modular rear frame unit secured together against relative longitudinal movement. The front frame unit has a post from which upper and lower rail sections extend in engagement with rail sections secured to a rear post which acts as a wheel mounting tube. The rail sections are interlinked by a spacer tube which carries a pivot sleeve of a cross-brace member. The upper rail section carries a mounting socket for a prefabricated backrest tube. The frame components may be prefinished for local assembly and permit a wide range of wheelchairs of different length, width and backrest configurations to be manufactured from a restricted range of standard parts.