Sepia mascarensis is a species of cuttlefish native to the western Indian Ocean, specifically Saya-de-Malha Bank (11°31′S 61°00′E / 11.517°S 61.000°E), Mascarene Ridge, and Cargados-Carajos Shoals. It lives at depths of between 87 and 325 m. S. mascarensis grows to a mantle length of 67 to 124 mm. The type specimen was collected in the Saya-de-Malha Bank, Indian Ocean. It is deposited at the Zoological Museum in Moscow.