Cycas bougainvilleana is a species of cycad in the genus Cycas, native to the islands northeast of Papua New Guinea, on New Britain, the Bismarck Archipelago and the Solomon Islands, where it occurs on or near the coast in calcareous coral sand dunes and in adjacent forests. The female cones are open, with sporophylls 7 cm long and 3.5–5 cm wide, and dense grey to orange tomentose, with 6-9 ovules per sporophyll. The sarcotesta is thick orange tomentose, and the sclerotesta flattened ovoid shaped. The male cones erect, narrow ovoid, with a broad apical spine.