Sunnyside is the name of a neighborhood in the Mid-Island region of Staten Island. The island is coterminous with the borough of Richmond, one of the five boroughs into which New York City, the USA's largest city, is divided.

Two large city parks — Silver Lake Park and Clove Lakes Park — form the eastern and western boundaries, respectively, of Sunnyside, which is named for a boarding house that was established there in 1889; the vicinity had previously been known as Clovenia, owing to its location in what was then referred to as the Clove Valley, whose name survives in Clove Road, which runs from West Brighton to Grasmere, and is one of the neighborhood's principal thoroughfares.

Prior to the advent of cable television service, Sunnyside was noted for having the worst television reception on Staten Island, a fact resulting from its being hemmed in by several hills, including Grymes Hill, Emerson Hill and Castleton Hill, the latter separating Sunnyside from neighboring Castleton Corners. In November of 1970 a public ice skating rink opened in Clove Lakes Park; soon after this it became the scene of a race riot between groups of Italian-American and African-American youths, this incident highlighting the tensions that have long existed between these two groups in New York City and a host of other cities throughout the northeastern United States.

Sunnyside was once the home of a campus of the College of Staten Island; located at the foot of Emerson Hill, in 1993 this campus was moved to the grounds of the former Willowbrook State School, and an advanced-placement high school, Michael Petrides, took its place.

A large percentage of Sunnyside's residents are civil service workers, this demographic trait being typical of many Mid-Island neighborhoods.