Samuel Greg (6 September 1804 - 14 May 1876) was an English industrialist and philanthropist.
Born in Manchester, the son of the elder Samuel Greg, the creator of Quarry Bank Mill, he was brother to William Rathbone Greg and Robert Hyde Greg. Influenced by the religious beliefs of his mother Hannah, he attended a Unitarian school in Nottingham. Further study in Bristol, under Lant Carpenter, and at the University of Edinburgh was interspersed with experience in the family firm and completed by the, then obligatory, Grand Tour.
Already more interested in the consequences of wealth rather than its creation, in 1830 and 1831 he gave lectures on scientific subjects to the workers at Quarry Bank. On his father's retirement in 1832, he took over management of Lowerhouse Mill in Bollington, Cheshire and used it as a basis for further social experimentation.
He published his ideas on the model factory village in Two Letters to Leonard Horner on the Capabilities of the Factory System (1840) and went on to found a number of educational and social institutions in Bollington. However, in 1847, he introduced new machinery in his mills which was so unpopular that it precipitated a strike.
In consequence, Greg suffered from a nervous breakdown and retired to his Bollington home, The Mount. Thereon, he restricted his philanthropy to scientific lectures for the workers of Macclesfield, becoming president of the Society for the Diffusion of Useful Knowledge.
He died in Bollington after a long illness. He had married Mary Priscilla Needham in 1838. She bore him two sons and six daughters.