Macleod, John James Rickard, 1876-1935, Scottish physiologist, educated at Aberdeen and Leipzig. He was a professor at Western Reserve Univ. (1903-18) and at the Univ. of Toronto (1918-28) and later taught at the Univ. of Aberdeen. For the discovery of insulin and the studies of its use in treating diabetes he shared with F. G. Banting the 1923 Nobel Prize in Physiology or Medicine. His works include Diabetes (1913), Physiology and Biochemistry in Modern Medicine (with others, 1918; 9th ed. Macleod's Physiology in Modern Medicine, 1941), and Carbohydrate Metabolism and Insulin (1926).

McLeod or MacLeod is a Scottish surname, derived from Clan MacLeod. The Gaelic form is Clann Mhic Leòid. Clann means children, while mhic is the genitive of mac, the Gaelic for son, and Leòid is the genitive of Leòd. The whole phrase therefore means The children of the son of Leod. The later form "McCloud" creates a connection to the English word "cloud" which did not originally exist.

People bearing the name "MacLeod" include: Persons named McLeod or MacLeod:

• A.A. MacLeod (20th century), Canadian politician from Ontario
• Alan Arnett McLeod (1899–1918), Canadian recipient of the Victoria Cross
• Alexander Samuel MacLeod (1888-1956), Canadian artist
• Alistair MacLeod (born 1936), Canadian author
• Ally McLeod (1931–2004), Scottish football player and manager
• Archibald McLeod, North West Company fur trader
• Bryan McLeod (born 1974), Canadian politician from Manitoba
• Charlotte MacLeod (1922–2005), Canadian mystery fiction writer
• Clarence J. McLeod (1895–1959)
• Cody McLeod (born 1984), Canadian professional ice hockey player
• Colin MacLeod (1909–1972), Canadian-American geneticist
• Donald McLeod (footballer) (1882–1917), English football (soccer) player
• Donald Kenneth McLeod (1885–1958), British Army officer with the British Indian Army
• Duncan Stuart McLeod (1854–1933), Canadian politician from Manitoba
• Duncan Lloyd McLeod (1874–1935), Canadian politician from Manitoba
• Fred McLeod (1882–1976), Scottish-American golfer
• Gavin MacLeod (born 1930), American actor
• George MacLeod (1895–1991), Scottish churchman, founder of the Iona Community
• Haggis McLeod (contemporary), British juggler and comedian
• Henry Dunning Macleod (1821–1902), Scottish economist
• H. G. McLeod (?–?), Inventor of the McLeod gauge
• Iain Macleod (1913–1970), British politician
• Ian R. MacLeod (born 1956), British science fiction and fantasy author
• Izale McLeod (born 1984), British footballer
• James Macleod (1836–1894), Scottish-Canadian pioneer and RCMP commissioner
• John James Richard Macleod (1876–1935), Scottish biochemist and co-discoverer of insulin
• Keith McLeod (born 1979), American basketball player
• Ken MacLeod (born 1954), Scottish science fiction writer
• Ken McLeod (born 1948), American Buddhist teacher, writer, translator
• Leah McLeod Australian television presenter and sister of Sarah McLeod
• Lyn McLeod (born 1942), Canadian politician from Ontario
• Malcolm Macleod, former Lord Rector of Edinburgh University
• Mary MacLeod Trump, deceased, Donald Trump's mother
• Mary McLeod Bethune (1875–1955), American educator
• Nathanel William Hamish Macleod (dates unknown), British Financial Secretary of Hong Kong 1991–1995
• Neil McLeod (1842–1915), Canadian politician from Prince Edward Island
• Neil McLeod (born 1952), New Zealand field hockey player
• Nicholas McLeod (fl. 1868–1889) Scottish businessman and missionary
• Norman MacLeod (1812–1872), Scottish theologian and Social Reformer.
• Norman Z. McLeod (1898-1964), film director
• Roshown McLeod (born 1975), Former American Basketball player
• Rudolf MacLeod, Dutch naval officer of Scottish ancestry and former husband of the famous WWI spy Mata Hari
• Samantha McLeod, Canadian actress
• Sarah McLeod (born 1971), New Zealand actress
• Sarah McLeod (singer) Australian singer, former frontwoman of The Superjesus
• Scott MacLeod, Scottish rugby union player
• Shane McLeod (born 1975), Australian news correspondent
• Stuart Macleod (born 1982), Scottish magicianFictional characters:
• Connor MacLeod, character from Highlander movies and television series
• Duncan MacLeod, character from Highlander movies and television series
• Justin McLeod, character from the film The Man Without a Face
• Claire McLeod, character from Australian Television Show McLeod's Daughters
• Tess Silverman McLeod Ryan, character from Australian Television Show McLeod's Daughters
• Jodi Fountain McLeod, character from Australian Television Show McLeod's DaughtersPlace names:
• Fort Macleod, town in Alberta, Canada
• McLeod (Edmonton), a residential neighbourhood in Edmonton, Canada
• Macleod, a federal electoral district in Alberta
• McLeod County, Minnesota, USA
• McLeod, North Dakota, USA
• MacLeod, suburb of Melbourne, Australia
• McLeod Ganj, town in Himachal Pradesh, IndiaOther:
• Clan MacLeod, Scottish clan
• Lake Macleod, lake in Western Australia
• McLeod's Daughters, Australian television drama
• McLeod gauge, scientific instrument to measure very low pressures
• McLeod syndrome, an anomaly of the Kell antigen system
• McLeod (tool), a hoe-like Wildland firefighting tool
• McLeod Lake, British Columbia, formerly Fort McLeod; named for Archibald McLeodSee also:
• Leod
• McCloud