John Glenn (1921–2016) was a United States astronaut and statesman.

John Glen or John Glenn may also refer to:

• John Glenn (judge) (1795–1853), Maryland attorney and federal judge
• John Glen (mayor) (1809–1895), mayor of Atlanta in 1855
• John Glenn (Alberta) (1833–1886), early Alberta settler
• John Thomas Glenn (1845–1899), mayor of Atlanta from 1889 to 1891
• John Glenn (1870s outfielder) (1850–1888), outfielder and first baseman in Major League Baseball from 1871 to 1877
• John Lyles Glenn Jr. (1892–1938), United States federal judge
• John Glenn (1960s outfielder) (1928–2023), outfielder in Major League Baseball in 1960.
• John Glen (director) (born 1932), English film director
• John Glen (politician) (born 1974), British politician
• John Glenn (screenwriter) (fl. 1999–2019), American director of The Lazarus Project

• John Glenn Middle School of International Studies, a middle school in Indio, California
• John Glenn High School (disambiguation), multiple schools in the United States

• USNS John Glenn (T-ESD-2)
• Fireboat John H. Glenn Jr.
• S.S. John Glenn, an Orbital-ATK Cygnus space capsule used on mission Cygnus CRS OA-7

• John (disambiguation)
• Glenn (disambiguation)
• John Glen (disambiguation)
• John Glynne (disambiguation)
• Jonathan Glenn (born 1987), Trinidadian soccer player