The Blue Idol Quaker Meeting House is a historic Quaker meeting house at Oldhouse Lane, Coolham, in the parish of Thakeham, near Horsham, West Sussex, England. The core of the building is a late sixteenth-century timber-framed farmhouse adapted for Quaker worship in the 1690s. It is listed at Grade II* on the National Heritage List for England for its architectural and historic interest, including its close association with the Quaker leader and proprietor of Pennsylvania, William Penn.