Hillsboro Airport (IATA: HIO, ICAO: KHIO), also known as Portland–Hillsboro Airport, is a corporate, general aviation and flight-training airport serving the city of Hillsboro, in Washington County, Oregon, United States. It is one of three airports in the Portland, Oregon, metropolitan area owned and operated by the Port of Portland. Established in 1928, it is Oregon's second busiest airport (in terms of total aircraft operations) at over 200,000 operations annually. HIO covers 900 acres (360 ha) and has three runways.

Located in the north-central area of Hillsboro, and west of Portland, it hosts the annual Oregon International Air Show. The airport includes a Federal Aviation Administration control tower, three paved runways, hangars, fueling facilities, and a small passenger terminal. Hillsboro Airport is also a port of entry, with a single-person U.S. Customs and Border Protection office.