Frullania is a large and taxonomically complex genus with over 300 accepted species. A new liverwort species, Frullania thouvenotiana sp. nov. from New Caledonia, is described and illustrated. The new species, and its placement in Frullania subg. Microfrullania, is based on morphology with support from previously published sequence data. Diagnostic characters associated with the leaf, especially the leaf margin, distinguishes it from all other species of Frullania, including similar species with a distribution comprising Fiji and New Zealand. A brief comparison is made with morphologically allied species, and an artificial key is provided. Frullania neocaledonica is also proposed to be a synonym of F. chevalieri.