Greenfield Hill is a neighborhood of Fairfield, Connecticut. Located in the northern part of the town, it extends from just south of the Merritt Parkway to the town's boundary with Easton, to the north.

Along with Southport, Greenfield Hill is one of two extremely wealthy neighborhoods in Fairfield. It is largely on account of Southport and Greenfield Hill that Fairfield is considered part of Connecticut's Gold Coast. Thanks in large part to the efforts of the Greenfield Hill Village Improvement Society, zoning is residential and lots are two acres or larger.

Just an hour north of New York City, Greenfield Hill’s shady lanes and meandering stone walls create an illusion of rural solitude. This agrarian community, which was established in 1725, has dwindled to a single working farm, as well as a horse stable that offers riding lessons. The remaining barns and pastures now function as artful additions to the landscape. Even the 19th century windmill that once pumped water for the area’s Jersey Cattle, has a more modern purpose – housing cellular phone antennas.

Locally, Greenfield Hill is known for its Dogwood Festival, which celebrates a variety of tree that abounds in the neighborhood. The dogwood has been a Greenfield Hill trademark since Dr. Isaac Bronson, an assistant surgeon in the Revolutionary War, decided to showcase them along the edges of his Bronson Road estate. In the early 1900’s the Greenfield Hill Village Improvement Society began importing and planting approximately 100 dogwoods a year. By the 1930’s, word had spread that the blooming of these trees was a sight worth traveling for and the famed Greenfield Hill Dogwood Festival was born.

The most famous and perhaps the most picturesque landmark is the Greenfield Hill Congregational Church, which presides over a classic New England green. Timothy Dwight IV, best known as a president of Yale University (and the namesake of one of its residential colleges) was pastor of Greenfield Hill Congregational Church for many years. According to local lore, he was hired by Yale to thwart plans for a rival educational institution in Fairfield.