Sierra Island (-62.4°N, -59.8°W) is a narrow island which is marked by a series of small elevations throughout its length, lying 0.5 mi northwest of Dee Island and north of Greenwich Island in the South Shetland Islands, Antarctica. Surface area 14 ha. Named by the 5th Chilean Antarctic Expedition, 1950–51, after Sgt. Victor Sierra, sick-bay attendant of the patrol ship Lientur on the expedition.