Coolham is a small village in the civil parish of Shipley and the Horsham District of West Sussex, England.

It is at the crossroads of the A272 and B2139 roads 2.8 miles (4.6 km) south-east of Billingshurst.

There was once a prominent Quaker community in Coolham, and the "Blue Idol" meeting house, a timber-framed building, still exists just under 1 mile to the west, in the adjacent parish of Thakeham.

William Penn, who earlier had founded Pennsylvania in America, was closely involved in its establishment, and is believed[by whom?]

Coolham is in the ancient parish of Shipley, which adjoins the A24, near the ruin of Knepp Castle.