'Sudbury' means the southern manor, south relative to Harrow.
The name was first recorded in the late 13th century as Suthbery, the southern manor house; its northern counterpart may have been the manor house of Harrow. Sudbury was one of ten hamlets in the larger of the Archbishop of Canterbury's two Harrow manors, and Sudbury Court was the archbishops' principal Middlesex residence until the end of the 14th century.