Ontario Provincial Highway #115 is a provincially maintained highway in Central Ontario, Canada. Highway 115 currently runs from the Highway 401 junction west of Newcastle to the Ontario Provincial Highway 7 Junction at Peterborough

The total length of Highway 115 is 58.4km

Highway 115 is part of the Algonquin Trail (south of the Ontario provincial highway 35 junction in Clarington) and part of the Trans-Canada Highway (east of Ontario provincial highway 7 junction south of Springville, Ontario). Highway 115 is a freeway between its junction with Ontario provincial highway 401 and Concession Rd. 3, from Concession Rd. 4 to Concession Rd. 8, and from its junction with Highway 35 to its junction with highway 7 at Peterborough. The other sections are classified as a RIRO expressway (right-in, right-out with special turnarounds). The freeway sections on the Highway 35 multiplex are substandard, below 400-series standards.

Highway 115 travels through Newcastle, Orono, Kirby, Cold Springs, and Peterborough. Highway 115 travels through the following municipalities: Clarington, Kawartha Lakes, Cavan-Millbrook-North Monaghan Township, and Peterborough. Highway 115 travels through the following counties: Durham, Kawartha Lakes, Peterborough County.

It has been speculated that once Highway 407 is complete to Enterprise Hill (it is uncertain whether that section will be MTO-operated or privately operated), the designation Highway 115 would be retired in favor of Highway 407, most likely under MTO jurisdiction, as the northern section is already up to 400-series standards.. That speculation is enhanced by the fact that south of Enterprise Hill on the RIRO/substandard freeway section, Highway 115 is multiplexed with Highway 35, which means no new designation would be required.