The Kāpiti Expressway is a four-lane grade-separated expressway on New Zealand's State Highway 1 route through the Kāpiti Coast north of Wellington. From the northernmost terminus of the Transmission Gully Motorway at Mackays Crossing just north of Paekākāriki, it extends northwards 31 km (19 mi) to just north of Ōtaki, bypassing the former two-lane route through Raumati South, Paraparaumu, Waikanae, Peka Peka, Te Horo and Ōtaki.

State Highway 1 is the longest and most significant road in the New Zealand road network, running the length of both main islands. It appears on road maps as SH 1 and on road signs as a white number 1 on a red shield, but it has the official designations SH 1N in the North Island, SH 1S in the South Island.