New York State Route 303 (NY 303) is a north–south state highway in eastern Rockland County, New York, in the United States. It begins at the New Jersey state line in the hamlet of Tappan and runs generally northward for 10.92 miles (17.57 km) to an intersection with U.S. Route 9W (US 9W) in Clarkstown. The route has connections to the Palisades Interstate Parkway and the New York State Thruway, the latter carrying Interstate 87 (I-87) and I-287. NY 303 was assigned as part of the 1930 renumbering of state highways in New York, and only minor realignments have occurred since that time.

Tappan is a hamlet and census-designated place in the town of Orangetown, Rockland County, New York. It is located northwest of Alpine, New Jersey, north of Northvale, New Jersey and Rockleigh, New Jersey, northeast of Old Tappan, New Jersey, east/southeast of Nauraushaun and Pearl River, south of Orangeburg, southwest of Sparkill, and west of Palisades; Tappan shares a border with each. The population was 6,673, according to the 2020 census.