King's Highway 108, commonly referred to as Highway 108, is a provincially maintained highway in the Canadian province of Ontario. Located in the Algoma District, the highway extends for 41.6 kilometres (25.8 mi) from an intersection with Highway 17 west of Serpent River, through the urban core of Elliot Lake, to an intersection with Quirke Mine Road in the north end of the city. The highway continues as Secondary Highway 639 north of Quirke Mine Road.

Algoma District is a district and census division in Northeastern Ontario in the Canadian province of Ontario.