Utricularia phusoidaoensis is a terrestrial lithophytic carnivorous plant that belongs to the genus Utricularia. It is endemic to the northern Thailand province of Phitsanulok on Phu Soi Dao, where it is only known from the type locality. It grows on wet cliffs at altitudes around 2,000 m (6,562 ft). It is related to U. garrettii, another species endemic to Thailand that shares a similar seed morphology. Utricularia phusoidaoensis is easily distinguished by its purple 4-6-lobed corolla, reniform leaves, and the staghorn-like trap appendages. It has been found growing in the presence of U. spinomarginata. It was first formally described by (of the Queen Sirikit Botanic Garden) and (of Trinity College, Dublin) in 2010 from collections made by Suksathan in 2007.