In a survey of the metazoan ecto- and endoparasites of Siganus sutor (Cuvier & Valenciennes, 1835), a commercially important herbivorous fish from the Kenyan coast, sixteen species of parasites are found. The gill parasites include Monogenea (Tetrancistrum sigani Goto & Kikuchi, 1917; Microcotyle mouwoi Ishii & Sawada, 1938; Pseudohaliotrema sp. 1 and sp. 2, and an unidentified Microcotylidae species); Copepoda (Caligus sp. and Hatschekia sp.); and Isopoda (one Gnathiidae species). The intestinal parasites found are Digenea (Opisthogonoporoides cf. hanumanthai Madhavi, 1972; Gyliauchen papillatus Goto & Matsudaira, 1918; Hexangium sigani Goto & Ozaki, 1929; and three other unidentified digeneans); Acanthocephala (Sclerocollum rubrimaris Schmidt & Paperna, 1978); and Nematoda (Procamallanus sigani Yamaguti, 1935). The species listed are first records for the Kenyan coast. Infection prevalence, mean intensity and site specificity are determined for the different parasite species. The parasites have an aggregated frequency distribution in the host population: some individuals of the siganid population are more heavily infected than expected in a random distribution, while others are very little or not at all infected.