King's Highway 402, commonly referred to as Highway 402 and historically as the Blue Water Bridge Approach, is a 400-series highway in the Canadian province of Ontario that connects the Blue Water Bridge international crossing near Sarnia to Highway 401 in London. It is one of multiple trade links between Ontario and the Midwestern United States. It is four lanes for much of its length, though the approach to the Blue Water Bridge is six lanes.

The 400-series highways are a network of controlled-access highways in the Canadian province of Ontario, forming a special subset of the provincial highway system. They are analogous to the Interstate Highway System in the United States or the Autoroute system of neighbouring Quebec, and are regulated by the Ministry of Transportation of Ontario (MTO). The 400-series designations were introduced in 1952, although Ontario had been constructing divided highways for two decades prior. Initially, only Highways 400, 401 and 402 were numbered; other designations followed in the subsequent decades. The network is situated almost entirely in Southern Ontario, although Highway 400 extends into the more remote northern portion of the province.