Lake Osveya or Lake Osveyskoye (Russian: озеро Осве́я, Осве́йское озеро, romanized:ozero Osveya, Osveyskoye ozero), also known as Lake Asvyeya (Belarusian: Асвейскае возера, romanized:Asviejskaje voziera), is a large freshwater lake in the Vitebsk Region, in northern Belarus, near the borders with Latvia and Russia. It has an area of 52.8 km2 (20 sq mi), making it the second largest lake in the country. The most extreme northern point in Belarus is situated only a few minutes further north of the lake.

The lake's sole island, Du[be], is the largest island in Belarus. Inhabited by a village and a kolkhoz until the 1970s, it is now a part of the Asviejski Landscape Reserve.