Based on DNA sequence data, the genus Leptosillia is shown to belong to the Xylariales. Molecular phylogenetic analyses of ITS-LSU rDNA sequence data and of a combined matrix of SSU-ITS-LSU rDNA, rpb1, rpb2, tef1 and tub2 reveal that the genera Cresporhaphis and Liberomyces are congeneric with Leptosillia. Coelosphaeria fusariospora, Leptorhaphis acerina, Leptorhaphis quercus f. macrospora, Leptorhaphis pinicola, Leptorhaphis wienkampii, Liberomyces pistaciae, Sphaeria muelleri and Zignoëlla slaptonensis are combined in Leptosillia, and all of these taxa except for C. fusariospora, L. pinicola and L. pistaciae are epitypified. Coelosphaeria fusariospora and Cresporhaphis rhoina are lectotypified. Liberomyces macrosporus and L. saliciphilus, which were isolated as phloem and sapwood endophytes, are shown to be synonyms of Leptosillia macrospora and L. wienkampii, respectively. All species formerly placed in Cresporhaphis that are now transferred to Leptosillia are revealed to be non-lichenized. Based on morphology and ecology, Cresporhaphis chibaensis is synonymised with Rhaphidicyrtis trichosporella, and C. rhoina is considered to be unrelated to the genus Leptosillia, but its generic affinities cannot be resolved in lack of DNA sequence data. Phylogenetic analyses place Leptosillia as sister taxon to Delonicicolaceae, and based on morphological and ecological differences, the new family Leptosilliaceae is established. Furfurella, a new genus with the three new species, F. luteostiolata, F. nigrescens and F. stromatica, growing on dead branches of mediterranean fabaceous shrubs from tribe Genisteae, is revealed to be the closest relative of Delonicicola in the family Delonicicolaceae, which is emended. ITS rDNA sequence data retrieved from GenBank demonstrate that the Leptosilliaceae were frequently isolated or sequenced as endophytes from temperate to tropical regions, and show that the genus Leptosillia represents a widely distributed component of endophyte communities of woody plants.