Soper Lake (Inuktitut: Tasiujajuaq, meaning "big lake-like lake") is a large, irregularly-shaped lake in Qikiqtaaluk Region, Nunavut, Canada. It is located on Baffin Island's Meta Incognita Peninsula. The Inuit name references the lake's meromictic attribute, a mixture of fresh and salt water caused by a set of reversing falls and 9–10 m (30–33 ft) tides in Pleasant Inlet.