Sir Reginald Henry Cox, 1st Baronet, DL (30 December 1865 – 27 March 1922) was an English banker. Cox was born in Westminster, the second son of Frederick Cox DL JP of Hillingdon House and Mabel Eden. He was educated at Eton. He was Senior Partner of Cox & Co and agent to the British Army. He was created a baronet, of Old Windsor in the County of Berkshire, in the 1921 New Year Honours. He lived in Old Windsor, Berkshire and was appointed a deputy lieutenant and selected High Sheriff of Berkshire for 1919–20.