Leptosillia is a fungal genus in the monogeneric family of Leptosilliaceae.

[2] The genus was circumscribed by Austrian mycologist Franz Xaver Rudolf von Höhnel in 1928.

[3] As the genus name suggests, Leptosillia was considered to be closely related to the diaporthalean genus of Sillia (in the Stilbosporaceae family, Diaporthales order).

[3] The genus was monotypic for a long time, containing only the type species, Leptosillia notha.

[4] Both families were then placed in order Delonicicolales, which forms a highly supported clade (100% ML).