Stylidium chiddarcoopingense (Stylidiaceae) is a new species of triggerplant endemic to south-west Western Australia. It is a member of the Stylidium caricifolium complex, in which seven species are now recognized. The other six species were described and illustrated in Lowrie et al. (1998). All members of the Stylidium caricifolium complex belong in subgenus Tolypangium Endl., section Squamosae Benth. (Mildbraed 1908).