Samuel Swett Green (February 20, 1837 – December 8, 1918) was an American librarian. Green was born in Worcester, Massachusetts, to the apothecary James Green and Elizabeth Swett. He was educated at Harvard, graduating in 1858. A few years later, he attended Harvard Divinity School but did not graduate until 1864 due to health issues. Forsaking the ministry, he began his library career in 1867, when he was appointed director of the Worcester Free Public Library. The library was heavily funded by Green’s uncle, Dr. John Green. As director, Green focused primarily on the technical aspects of librarianship. He also instituted an interlibrary loan system and a lending collection of artwork. In 1871, he took up the position of librarian, a position he held for 38 years. Green was elected a member of the American Antiquarian Society in 1880.