Caladenia ambusta, commonly known as the Boranup spider orchid, is a plant in the orchid family Orchidaceae and is endemic to the south-west of Western Australia. It has a single erect, linear leaf and a single creamy-coloured flower on a stem 27–35 cm (11–14 in) high. It is only known from a relatively small area south-west of Margaret River growing in deep sand in shrubland and woodland and only flowering profusely after fire.