Robert Cowan (died 21 February 1737) was an Irish colonial administrator and the East India Company's Governor of Bombay from 1729 to 1734. He was a collateral ancestor of the Marquesses of Londonderry through the marriage of his sister, Mary Cowan, to Alexander Stewart, father of Robert Stewart, 1st Marquess of Londonderry.
Cowan was descended from Ulster Scots Presbyterian stock, and his father, John Cowan, was an Alderman of the city of Derry. He entered the service of the East India Company some time before 1720 and retired in 1735, two years before his death. In 1721, he was involved in an unsuccessful campaign against Kanhoji Angre. His personal fortune, amassed as governor, became part of the basis of the wealth of the Stewart family for generations.