The Arthur Kill is a tidal strait separating Staten Island, New York from mainland New Jersey, USA, and a major navigational channel of the Port of New York and New Jersey. Arthur Kill has also been known as Staten Island Sound.

The channel is approximately 10 miles (16 km) long and connects Raritan Bay on its south end with Newark Bay on the north. Along the New Jersey side it is primarily lined with industrial sites, part of which is called the Chemical Coast. The Staten Island side, it is primarily lined with salt marshes.

A heavily used marine channel, it provides access for ocean-going container ships to Port Newark and to industrial facilities along the channel itself. It also provides the primary marine access to the now-closed Fresh Kills Landfill on Staten Island.

The channel is dredged periodically to a depth of 35–37 feet (11 m) and a width of 600 feet (183 m) to maintain its usefulness for commercial ship passage.

Because of the complex nature of the tides in New York-New Jersey Harbor Estuary near the mouth of the Hudson River, the hydrology of the Arthur Kill is still an open subject. In particular, the net flow of the channel is not well established.