Molecular sequence data of the ITS barcoding locus were employed to clarify the taxonomy of Hawaiian species of Pseudocyphellaria s.lat., including the recently segregated genera Crocodia and Podostictina. Based on published checklists and taxonomic and nomenclatural revisions, Hawaii was supposed to harbor seven widespread species, with zero degree of endemism: P. argyracea, P. aurata, P. crocata, P. dissimulata, P. intricata, P. pickeringii and P. punctillaris. Our results show that there are at least 12 species in the archipelago (one each in Crocodia and Podostictina, and ten in Pseudocyphellaria s.str.). Of the previously reported species, only the presence of Crocodia aurata was confirmed. Reports of Pseudocyphellaria crocata refer to no less than six species, four of them new to science: P. biliana Moncada, Reidy & Lücking, P. longiloba Moncada, Reidy & Lücking, P. philipiana Moncada, Reidy & Lücking, and P. pomaikaiana Moncada, Reidy & Lücking. Pseudocyphellaria hawaiiensis H. Magn. and P. xanthosticta (Pers.) Moncada & Lücking, comb. nov. [ =  Sticta crocata f. sandwicensis Zahlbr.] are reinstated, whereas P. crocata s.str. does not occur in Hawaii. Pseudocyphellaria perpetua McCune & Miądl., described from North America, is established as a synonym of P. hawaiiensis. Reports of P. argyracea, P. intricata and P. punctillaris refer to three newly described species, P. confusa Moncada, Reidy & Lücking, P. gallowayana Moncada, Reidy & Lücking and P. macroisidiata Moncada, Reidy & Lücking, and the reinstated P. horridula (Zahlbr.) H. Magn. Material identified as P. flavicans and P. pickeringii is not identical with either species but represents another new taxon, P. cliffordiana Moncada, Reidy & Lücking. Based on these findings, the degree of inferred endemism in Hawaiian Pseudocyphellaria s.lat. is 75%, higher than suggested even in early treatments. The following further six new combinations are proposed—Podostictina ardesiaca (D.J. Galloway) Moncada & Lücking, comb. nov., P. berberina (G. Forst.) Moncada & Lücking, comb. nov., P. compar (Nyl.) Moncada & Lücking, comb. nov., P. degelii (D.J. Galloway & P. James) Moncada & Lücking, comb. nov., P. flavicans (Hook. f. & Taylor) Moncada & Lücking, comb. nov. and P. pickeringii (Tuck.) Moncada & Lücking, comb. nov.