Sir Simon Michael Hornby FBIM FRSA (29 December 1934 – 17 July 2010) was a British businessman. He was chairman of WHSmith, the British retail chain, the Royal Horticultural Society and the Design Council. He founded the National Literacy Trust.
Simon Michael Hornby was born on 29 December 1934 in London. He was the son of Michael Hornby and grandson of St John Hornby. He was educated at Eton College, New College, Oxford and Harvard Business School. He served in the Grenadier Guards as a 2nd Lieutenant from 1953-55.
He married Sheran Cazalet, the sister of his friend, the high court judge Sir Edward Cazalet, and daughter of the Queen Mother's horse trainer Peter Cazalet. They did not have any children.
Hornby was knighted in the 1988 New Year Honours.