Xanthoparmelia sleei is a species of foliose lichen in the family Parmeliaceae,[1] first described by John Alan Elix in 2003.

The upper surface is initially yellow-green and becomes darker over time, featuring a smooth, shiny texture that turns dull and rugulose with age.

[2] The lower surface is smooth, ranging from ivory to tan or brown, and darker at the lobes' apices.

[2] The lichen produces scattered apothecia, which are up to 1.0 mm wide, with a concave, dark brown disc.

[2] Xanthoparmelia sleei is found on laterite and granite rocks within dry, shrubby, sclerophyll forests and heathlands.