The Greenwich Country Day School is a co-educational, independent day school in Greenwich, Connecticut, United States, founded in 1926.

In November 2017, Greenwich Country Day acquired The Stanwich School, making it the only independent nursery through 12th grade co-educational school in Greenwich.

It is accredited by the State of Connecticut through the New England Association of Schools and Colleges and is a member of the National Association of Independent Schools.

The school is located on a rolling campus set into a series of hills.

The Old Church Road campus is divided into three distinct schools, and the Upper School is on a separate campus on Stanwich Road.