John Brown most often refers to:
John Brown (abolitionist) (1800–1859), American who led an anti-slavery raid on Harpers Ferry, Virginia, in 1859
John Brown or Johnny Brown may also refer to:
Academia
John Brown (educator) (1763–1842), Irish educator; third president of the University of Georgia
John Carter Brown (1797–1874), American book collector and antiquarian
John Macmillan Brown (1845–1935), Scottish-New Zealand academic, administrator and promoter of education for women
John Nicholas Brown I (1861–1900), American book collector and antiquarian
John Lott Brown (1924–2011), American university administrator and professor
John H. Brown (scholar) (born 1948), American scholar of public diplomacy
Arts and entertainment
Literature
John Brown (historian) (died c. 1829), English miscellaneous writer
John Mason Brown (1900–1969), American literary critic
Sir John Gilbert Newton Brown (1916–2003), English book publisher
John Gregory Brown (born 1960), American novelist
John Brown (American author) (born 1966), American novelist and short story writer
Performing arts
John Browne (composer) (1453–c. 1500), English composer
John Brown (actor) (1904–1957), English radio and film actor
Johnny Mack Brown (1904–1974), American film actor and college football player
Johnny Brown (actor) (1937–2022), American actor and singer
John Moulder-Brown (born 1953), English actor
John W. Brown (set decorator) (fl. 1960s–1970s)
Visual arts
John Brown (artist) (1752–1787), Scottish artist
John Crawford Brown (1805–1867), Scottish landscape painter
John Lewis Brown (1829–1892), French battle, animal, and genre painter
John George Brown (1831–1913), English-born American painter
John William Brown (artist) (1842–1928), English painter and stained-glass designer
John Appleton Brown (1844–1902), American painter
John Arnesby Brown (1866–1955), English landscape artist
Business and industry
John Brown (1723–1808), Scottish-Danish merchant and shipowner
John Brown (brewer) (1795–1890), English brewer
John Brown (builder) (1809–1876), Canadian builder
John Brown (coalmine owner) (1850–1930), coal baron and shipowner in New South Wales, Australia
Sir John Brown (industrialist) (1816–1896), British industrialist; founder of the Atlas steelworks
John Albert Brown (1885–1944), American oilman and president of Mobil
John Bundy Brown (1805–1881, American industrialist, owner of the Portland Sugar Company
John Crosby Brown (1838–1909), American banker; partner in Brown Bros. & Co.
John W. Brown (labor leader) (1867–1941), Canadian-born labor leader in the United States
John Brown (trade unionist) (1880/81–1961), British trade union leader and local councilor
John W. Brown (British trade unionist) (1886–?), British activist, general secretary of the International Federation of Trade Unions
John Seely Brown (born 1940), American researcher in organizational studies
John W. Brown (corporate executive) (fl. 1980s–2010s), American executive; president of Stryker Corporation
Military
John Brown (British Army officer, died 1762), British Army general
John Brown (British Army soldier) (1908–1965), Royal Artillery quartermaster sergeant and espionage agent
John Brown of Pittsfield (1744–1780), American Revolutionary War officer
John Brown (sailor) (1826–1883), American sailor and Civil War Medal of Honor recipient
John Harties Brown (1834–1905), Canadian soldier who fought in the American Civil War
John Brown (Medal of Honor) (c. 1838–?), American sailor and peacetime Medal of Honor recipient
John H. Brown (Medal of Honor) (1842–1898), American soldier and Civil War Medal of Honor recipient
John H. Brown Jr. (1891–1963), United States Navy admiral and American football player
John Nicholas Brown II (1900–1979), U.S. Assistant Secretary of the Navy
John Brown Jr. (Navajo code talker) (1921–2009), American Navajo code talker during World War II
John M. Brown III (fl. 1960s–2000s), United States Army general
John S. Brown (general) (born 1949), United States Army brigadier general; Chief Historian of the United States Army Center of Military History
John Marshall Brown (1838–1907), American commissioned officer during the American Civil War