Alexander Cowan (17 June 1775 – 13 February 1859) was a Scottish papermaker and philanthropist. He was a cousin and friend of Thomas Chalmers, the prominent Scottish minister. Through his business he was a friend and associate of the publisher Archibald Constable and, through Constable, an associate of Sir Walter Scott. Cowan owned and ran the huge Valleyfield paper-works in Penicuik in Midlothian.
Cowan was born at Valleyfield on the edge of Penicuik on the banks of the North Esk. He studied physics and chemistry in Edinburgh, and decided to improve the process of paper-making, setting up what was then one of the world's largest mills, which operated for 150 years.
He married Elizabeth Hall, daughter of George Hall, a merchant in Crail, in Fife, in 1800. The couple had several sons, all involved in the family business. Their first child, Charles, was born in 1801 at their house at 12 Charlotte Street, the first of Cowan's eleven children, eight of whom survived to adulthood.
Cowan moved his family to Edinburgh in 1811, which some accounts connect to the illness of his wife Elizabeth. By 1814, when their son John was born, they were living at 5 John Street, a house just off the Canongate, but not part of the Old Moray House as recorded in some records. Elizabeth died on 21 March 1822. In 1830 he married Helen Brodie. Soon after he opened a paper shop at 17 Princes Street in Edinburgh city centre. At the same time he moved a short distance, but to a far grander house, Moray House on the Canongate.
He is known to have been a friend of the botanist Daniel Ellis during this period.
His sons also rose to prominence. Charles Cowan and James Cowan became MPs representing Edinburgh, and Sir John Cowan was created a baronet in 1894.