Lake Kuttara (倶多楽湖) is a nearly circular caldera lake in Shiraoi, Hokkaidō, Japan. It is part of Shikotsu-Tōya National Park. The lake is recognized as having the best water quality in all of Japan. With a transparency of 19 m, the lake ranks second to Lake Mashū according to the Ministry of the Environment. Resident species of the lake include a salamander species, Ezo salamander (エゾサンショウウオ). Since 1909, Sockeye salmon have been introduced to the lake.