Samuel Greg (26 March 1758 – 4 June 1834) was an Irish-born industrialist and entrepreneur of the early Industrial Revolution and a pioneer of the factory system. He built Quarry Bank Mill, which at his retirement was the largest textile mill in the country. He and his wife Hannah Greg assumed welfare responsibilities for their employees, many of whom were children, building a model village alongside the factory. At the same time, Greg inherited and operated a slave plantation in the West Indies.