Bruncu Spina, Mountain summit in the Gennargentu massif, Sardinia, Italy

Bruncu Spina is a mountain summit in the Gennargentu massif that rises to 1,829 meters (6,001 feet). Its steep slopes are covered with low scrubland vegetation, transitioning to holm oak woodlands at lower elevations.

The Sardinian toponym Bruncu Spina is translated as "cima del cardo" (thistle summit), after the Asteraceae herbs on the mountain; the linguist Massimo Pittau instead reads it as "cima della spina", referring to Prunus prostrata growing there. An astronomical observatory once stood on the summit and is now a ruin.

The Sardinian name Bruncu Spina means "thistle summit", after the Asteraceae herbs on the slopes; others link it to Prunus prostrata, a creeping thorny shrub. Herders from Fonni hold traditional civic rights on the Villagrande Strisaili side, grazing cattle that shelter in two abandoned mountain huts during bad weather.

The summit is reached by two trails maintained by the Ente Foreste della Sardegna: the Gennargentu T-721, 5.3 km with 149 m of ascent, and the T-721A branch from Arcu Artilai, about 800 m with 168 m of ascent. Snow can persist into May or June, and winter temperatures drop to -30 °C with wind chill near -40 °C.

On the summit stood an astronomical observatory, now reduced to a ruin. The peak also lies under a layer of permafrost that never thaws, and snowfields persist in sheltered hollows until May or June.