Jayjay Lake is a teardrop-shaped lake in the Canadian province of Saskatchewan. It is in the Northern Saskatchewan Administration District and access is from Highway 165. The lake is situated at the north-eastern slopes of the Cub Hills in the Mid-Boreal Uplands Ecoregion. It is surrounded by muskeg in a boreal forest of pine, birch, aspen, and spruce.

Jayjay Lake is within the Sturgeon-Weir River watershed. Sturgeon-Weir River is a tributary of the Saskatchewan River. Jayjay Creek flows out of Jayjay Lake at its north end and flows south-east into Big Sandy Lake.

Jayjay Lake Recreation Site (54°30′49″N 104°13′32″W / 54.5136°N 104.2256°W / 54.5136; -104.2256) is a provincial recreation site on the eastern shore of Jayjay Lake. There is free camping and lake access for fishing and other water sports. The lake is restricted to non-motorised boats only.

Fish commonly found in Jayjay Lake include yellow perch and northern pike.

• List of lakes of Saskatchewan
• Tourism in Saskatchewan