John Gregg may refer to:
Politicians John Gregg (Guildford MP) (died 1431 or after), English MP for Guildford John Gregg (Texas politician) (1828–1864), American politician from Texas who was killed in action during the American Civil War John R. Gregg (born 1954), American politician from Indiana
Religion John Gregg (bishop of Cork) (1798–1878), Anglican Bishop of Cork, Cloyne and Ross, 1862–1878 John Gregg (archbishop of Armagh) (1873–1961), Anglican Archbishop of Armagh 1939–1959
Others John Irvin Gregg (1826–1892), United States Army general John Robert Gregg (1867–1948), Irish-born American inventor of Gregg shorthand John P. Gregg (1876–1963), head football coach at Louisiana State University, 1899 John William Gregg (1880–1969), American landscape architect John Gregg (1899–1986), companion of philanthropist Robert Allerton John Gregg (baker) (1909–1964), British founder of Greggs bakery John Gregg (actor) (1939–2021), Australian actor John Gregg (loyalist) (1957–2003), Ulster loyalist, member of the UDA
See also John Gregg Fee (1816–1901), founder of Berea College John Greig (disambiguation)