The genus Parsonsia is revised in the Malesian region. Lyonsia, Helygia, Cudicia, Chaetosus, Delphyodon, and Grisseea are included in synonymy and 27 species are recognised, one of which has 7 varieties. There are 9 new species, 4 new varieties, 2 new combinations and 2 new statuses, one of which is also a new combination.