Cladonia sipmanii is a species of fruticose lichen in the family Cladoniaceae.

Found in Guyana, it was formally described as a new species in 2000 by Finnish lichenologist Teuvo Ahti.

The type specimen was collected by the author from Demerara-Mahaica region; it also occurs in the Guayana Region of Venezuela.

It grows in sandy soil and on sandstone; typical habitat includes coastal savannahs.

This Lecanorales-related article is a stub.