Ablation Lake is a proglacial tidal lake in Ablation Valley, Alexander Island, Antarctica, with stratified saline and fresh water and depths exceeding 117 m. The feature is dammed in the upper portion by ice that pushes into the lake from the adjacent George VI Ice Shelf. It is named after Ablation Valley following British Antarctic Survey (BAS) limnological research from 1973. The site lies within Antarctic Specially Protected Area (ASPA) No.147. The lake has a sub-ice channel connecting it to George VI Sound, and is approximately 500 m below the surface of the ice.