Mortimer is a masculine given name which may refer to:
- Mortimer J. Adler (1902–2001), American philosopher, educator and author
- Mortimer Caplin (1916–2019), American lawyer and educator
- Mortimer Cleveland (1883–?), American architect
- Mortimer Collins (1827–1876), English poet and novelist
- Mortimer Davis (1866–1928), Canadian businessman and philanthropist
- Mortimer Durand (1850–1924), British diplomat and civil servant in British India
- Mortimer Fitzland Elliott (1839–1920), American politician
- Mortimer Hogan (1862–1923), American Major League Baseball outfielder
- Mortimer von Kessel (1893–1981), German World War II general
- Mort Leav (1916–2005), American comic book and advertising artist
- Mortimer Dormer Leggett (1821–1896), American lawyer, school administrator, professor and Union Army major general during the American Civil War
- Mortimer Lewis (1796–1879), English architect and surveyor; Colonial Architect in New South Wales
- Mortimer Menpes (1855–1938), Australian-born artist, author, printmaker and illustrator
- Mortimer M. Miller (1929–2017), American politician and writer
- Mortimer Mishkin (1926–2021), American neuropsychologist
- Mortimer L. Neinken (1896–1984), American stamp collector
- Mortimer Planno (1929–2006), drummer and Rastafari elder best known as the Rasta teacher of Bob Marley
- Mortimer R. Proctor (1889–1968), American politician, 66th governor of Vermont
- Mortimer Sackler (1916–2010), American physician, entrepreneur and philanthropist
- Mortimer L. Schiff (1877–1931), American banker and Boy Scouts of America leader
- Mortimer Singer (1863–1929), Anglo-American landowner, philanthropist, sportsman and early pilot
- Mortimer Thomson (1832–1875), American journalist and humorist
- Mortimer Tollemache (1872–1950), English cricketer
- Mortimer von Maltzan (1793–1843), Prussian diplomat and Foreign Minister
- Mort Weisinger (1915–1978), American magazine and comic book editor
- Mortimer Wheeler (1890–1976), British archaeologist
- Mortimer Wilson (1876–1932), American composer of classical music
- Mortimer Zuckerman (born 1937), Canadian-born American businessman