Robert J. Miller Air Park (IATA: MJX, ICAO: KMJX, FAA LID: MJX, formerly N44), also known as the Ocean County Airport, is a county-owned public-use airport in Ocean County, New Jersey, United States. It is located five nautical miles (6 mi, 9 km) southwest of the central business district of Toms River, New Jersey.

Opened in 1968 as the Ocean County Air-Park, the airport is named after Ocean County Freeholder Robert J. Miller, who worked to expand the airport while in office. Miller died in 1969 in an accident that occurred at the airport; it was named after him in 1970.

This airport is included in the FAA's National Plan of Integrated Airport Systems for 2011–2015, which categorized it as a general aviation airport.