Coombe Keynes is a hamlet and civil parish in the Purbeck district of the English county of Dorset. It is situated about west-south-west of Wareham. In 2013 the estimated population of the civil parish was 80. There are 22 houses in the hamlet itself and 37 properties across the parish as a whole.
Coombe Keynes was historically part of the Winfrith Hundred. It appears in the Domesday Book (as Cume), when it was held by Gilbert de Magminot, Bishop of Lisieux. The name Keynes derives from the later Lords of the Manor, the de Cahaignes family, who also held Tarrant Keyneston.
Holy Rood Church in Coombe Keynes was formerly the centre of a large parish which included the nearby village of Wool. This was until 1844 when Wool was established as a separate parish. Finally, the parish of Coombe was merged into that of Wool in 1967. The church dates from the 13th century. It was much restored in 1860-1, although the west tower and chancel arch were unaltered. The church is now used as a function room managed by the Coombe Keynes Trust. The Coombe Keynes Chalice, a rare pre-Reformation chalice with an octagonal foot with embellished angles on the stem, is now kept in the Victoria and Albert Museum.