Microtripus tinggiensis, a new genus and species (Amphipoda: Caprellidea: Phtisicidae), was discovered in the interstitial benthos from Pulau Tinggi, an island in the East Johor Islands Archipelago (EJIA). Microtripus tinggiensis is distinct in its reduced pereopods 3–5 (1-articulate pereopods 3, 4 and 3-articulate pereopod 5). The new genus Microtripus most closely resembles Perotripus Dougherty & Steinberg, 1953 in its elongated body segments, shorter antennae 1 and 2 and gills on pereonites 2–4 but differs from the latter by its 3-articulate flagellum of antenna 1 and 1-articulate, vestigial pereopod 3.