Sticta tainorum is a rare species of foliose lichen in the family Peltigeraceae.

Found in Puerto Rico, it was formally described as a new species in 2020 by Joel Mercado‐Díaz and Robert Lücking.

The type specimen was collected by the first author in Toro Negro State Forest at an elevation of 1,036 m (3,399 ft).

It is only known to occur on a few trees in high-elevation forests on the eastern part of the island, near Pico Doña Juana.

The specific epithet refers to the indigenous Taíno people.