Tasialuk (Inuktitut syllabics: ᑕᓯᐊᓗᒃ[1]) formerly Ayr Lake[2] is a land-locked freshwater lake, structurally a fjord, on Baffin Island's northeastern coast in the Qikiqtaaluk Region of Nunavut, Canada.

Tasialuk is located east of the Kangiqtualuk Uqquqti and Arviqtujuq Kangiqtua fjords.

The Kuugaaluk flows out of the northern end of the lake and discharges its waters in the Baffin Bay a further 40 km (25 mi) to the northeast.

[3] There are spectacular landscapes in Tasialuk, with massive nearly 1,400 m (4,600 ft) high summits rising their ramparts close to the shore, especially in its central part.

[4] In the inner area the Ayr Pass connects with the Arviqtujuq Kangiqtua to the west.