The genus Krakatauia Enderlein is revised for the southwest Pacific. Based on existing collections and newly collected material from Fiji, 29 species are treated and keyed, including 25 newly described species. The alanae group includes three species from Fiji, K. luctuosa (Parent), K. lamiensis n. sp., and K. moanakaka n. sp. The alanae group is defined by strong synapomorphies in the male hypopygial structure and also includes two species from eastern Australia. The nupta group comprises three species at the easternmost limit of Krakatauia: K. nupta (Bezzi) from Fiji, and two new species, K. cicia n. sp. from the Lau Group, and K. planticorum n. sp. from Tonga & Niue. The evulgata group is diverse in the western Pacific, and notes and new records are provided for
the widespread species K. evulgata (Becker) and K. micronesiana Bickel. Three species are newly described: K. hutuna n. sp., from the Solomon Islands, and K. ounua n. sp. and K. tanna n. sp., both from Vanuatu. The malakula group is a poorly defined assemblage that includes five newly described species: K. cheesmanae n. sp., K. epiensis n. sp., and K. malakula n. sp., all from Vanuatu, K. graciosa n. sp., from the Solomon Islands, and K. sigatoka n. sp., from Fiji. The Krakatauia abaca group comprises a large radiation within the Fijian Archipelago, especially in upland forests on the main islands, with 13 newly described species: K. abaca n. sp., K. auribarba n. sp., K. bisignata n. sp., K. bouma n. sp., K. evodevo n. sp., K. hurleyi n. sp., K. korobaba n. sp., K. namatalaui n. sp., K. natewa n. sp., K. navai n. sp., K. solodamu n. sp., K. tomaniivi n. sp., and K. vuda n. sp. Most of these species are from single sites or adjacent sites, suggesting a high level of local endemicity. Of particular interest is the diversity of antennal flags, almost all of them diagnostic at the species level, and probably used in species recognition during courtship. Some of these flags have distinctly different obverse sides, and one species K. bisignata, has a three dimensional structure, with a white vane perpendicular to the underlying black flag.