Green Brook is a tributary of the Raritan River in central New Jersey in the United States.

It continues flowing southwest and turns south before the Ambrose Brook joins it at the intersection of Lincoln Blvd.

The Green Brook Flood Control Project in Somerset County in central New Jersey was first proposed in the early 1970s in the wake of two major floods in June 1971 and August 1973, which caused millions of dollars of property damage and several deaths along the Green Brook and Raritan Rivers.

Hurricane Floyd in 1999 caused additional property damage and deaths in the Green Brook basin, renewing interest in the flood control project.

Some construction related to the project has been completed since 1999, particularly in Bound Brook, but federal funding limitations have slowed progress in recent years.