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

• Antwan McClellan, American politician
• Barr McClellan, Texas lawyer and author, father of Mark and Scott McClellan
• Beverly McClellan (1969–2018), American singer and contestant in the first season of the American TV series The Voice
• Brian McClellan, American writer of fantasy
• C. M. S. McLellan (1865–1916), American playwright and composer, also wrote as Hugh Morton
• Edwin North McClellan (1881–1971), United States Marine Corps officer, author, and historian
• George McClellan (New York politician) (1856–1927), U.S. Representative from New York
• George McClellan (physician) (1796–1847), surgeon and founder of Jefferson Medical College in Philadelphia, Pennsylvania
• George McClellan (police officer) (1908–1982), Commissioner of the Royal Canadian Mounted Police
• George B. McClellan (1826–1885), American Civil War general and creator of the Army of the Potomac
• George B. McClellan Jr. (1865–1940), Mayor of New York City and U.S. Representative from New York
• George Marion McClellan (1860-1934), American writer
• Gerald McClellan American former professional boxer
• James E. McClellan (1926–2016), American veterinarian and politician
• James H. McClellan, mathematician and electronic engineer, professor at Georgia Institute of Technology
• Jase McClellan (born 2002), American football player
• John McClellan (chemist) (1810–1881), English chemist and industrialist
• John L. McClellan (1896–1977), U.S. Senator from Arkansas
• Joseph McClellan (1746–1834), American soldier and politician
• Katherine Elizabeth McClellan (1859-1934), American photographer
• Mark McClellan (born 1963), Medicare and FDA official
• Mike McLellan (born 1981), Canadian indoor lacrosse player
• Peter McClellan, Australian jurist
• Robert McClellan (1806–1860), U.S. Representative from New York
• Robert McClellan (New York treasurer) (1747–1817), treasurer of New York state
• Robert H. McClellan (1823–1902), Illinois state senator
• Robert L. McClellan (1822–1889), American politician and lawyer from Pennsylvania
• Samuel McClellan (1730–1807), brigadier general in the American Revolutionary War
• Scott McClellan (born 1968), former White House press secretary
• Sid McClellan (1925–2000), footballer who played for Tottenham Hotspur, Portsmouth and Leyton Orient.
• Stephen T. McClellan, Wall Street analyst, author
• Thomas N. McClellan (1853–1906), associate justice and chief justice of the Supreme Court of Alabama

Fictional characters:

• Clarisse McClellan, a character in Fahrenheit 451 by Ray Bradbury
• "Mrs. McClellan," a character without a first name in Ray Bradbury's story "There Will Come Soft Rains."