Lay is a surname. Notable people with the surname include:

• Alfred Morrison Lay (1836–1879), U.S. politician
• Beirne Lay, Jr. (1909–1982), American author and World War II aviator
• Benjamin Lay (1681–1760), English Quaker and abolitionist
• Bob Lay (1944–2022), Australian sprinter
• Caren Lay (born 1972), German politician
• Carol Lay (born 1952), American author
• Cecil Howard Lay (1885–1956), English poet
• Charles Downing Lay (1877–1956), American landscape architect
• Donald P. Lay (1926–2007), American jurist
• Elzy Lay (1868–1934), U.S. outlaw
• George W. Lay (1798-1860), U.S. politician
• George Tradescant Lay (c. 1800–1845), British naturalist, missionary and diplomat
• Herman Lay (1909–1982), American businessman
• Horatio Nelson Lay (1832–1898), British diplomat
• Humberto Lay (born 25 September 1934), Peruvian evangelical pastor
• Jeffrey Lay (born 1969), Canadian rower
• John Louis Lay (1832–1899), American inventor
• Josh Lay (born 1982), American football player
• Kenneth Lay (1942–2006), U.S. businessman
• Ken Lay (police officer) (born 1956), Australian police commissioner
• Ko Lay (born 31 October 1931), Burmese politician
• Oliver Ingraham Lay (1845-1890), American portrait painter.
• Sam Lay (1935–2022), American drummer and vocalist
• Stan Lay (1906–2003), New Zealand track and field athlete
• Susan Lay (born March 13, 1985), English actress, musician, and TV presenter