Adams Lake, Glacial lake in Thompson-Nicola Regional District, Canada.

Adams Lake is a long, narrow, fjord-like lake in south-central British Columbia, separating the Thompson and Shuswap regions. It runs about 63 kilometres north to south, with a surface elevation of 404 metres and a maximum depth of 457 metres. Squaam Bay on the west shore is the only major indentation, and the upper reaches lie in the northern Monashee Mountains.

The lake is named after Chief Adam, a Secwepemc leader who was baptized by Father Nobli and took the name Adam; his Secwepemc name was Sel-howt-kin (sometimes spelled Atahm). He died in the 1862 Pacific Northwest smallpox epidemic, which according to James Teit killed over half the local Secwepemc population. The name appeared in print by September 1866, and George Mercer Dawson surveyed the area in 1877, 1882 and 1898.

The lake's name honours Chief Adam (Atahm), a Secwepemc chief baptized by Father Nobli, who died in the 1862 smallpox epidemic. Pictographs at White Bluffs and north of Tshinakin Point mark culturally important rock faces, and a small cave upslope provided ochre mixed with animal fat for ceremonial paint.

The southern end lies about 79 km northeast of Kamloops by road. The lake is long and narrow, with Squaam Bay the only major indentation on the west shore. The water stays cold even in summer, and weather in the surrounding mountains can change quickly.

With a mean depth of 299 metres and a maximum of 457 metres, Adams Lake is the second deepest lake in British Columbia after Quesnel Lake, and seventh deepest in the world by mean depth. Its size and depth trap sediment washed in from tributaries such as Hiuihill (Bear) Creek, keeping the water cold and clear for salmon spawning in the lower Adams River.