Sphenomorphus forbesi, also known commonly as Forbes' forest skink and the slender litter skink, is a species of lizard in the family Scincidae.

The species is endemic to Papua New Guinea.

[2] The specific name, forbesi, is in honor of Henry Ogg Forbes, who was a Scottish explorer and naturalist.

[3] S. forbesi is found on the Sogeri Plateau in the Owen Stanley Range in Central Province, Papua New Guinea.

[1][2] The preferred natural habitat of S. forbesi is forest, at altitudes of 700–1,900 m (2,300–6,200 ft), but it has also been found in oil palm plantations.