•
Katherine Burns Mabry (1886–1958), one of New Mexico's first female lawyers •
Katherine MacDonald (1891–1956), American stage and film actress •
Katherine MacGregor (1925–2018), American actress •
Katherine Duer Mackay (1878–1930), American suffragist •
Katherine Mackay (1901–1975), Australian police officer •
Katherine MacLean (1925–2019), American science fiction author •
Katherine Stewart MacPhail (1887–1974), Scottish surgeon •
Katherine Magarian (1906–2000), survivor of the Armenian genocide •
Katherine Magbanua (born 1984/1985), American convicted murderer •
Katherine Maher (born 1983), American businesswoman •
Katherine Maine (born 1997), Canadian professional racing cyclist •
Katherine Manion (1867–1956), American physician and suffragist •
Katherine Manners, English actress, screenwriter, and playwright •
Katherine Mansfield (1888–1923), New Zealand writer and critic •
Katherine Maraman (born 1951), American judge •
Katherine Marsh (born 1974), writer of children's literature •
Katherine Martínez, Venezuelan lawyer, activist, and human rights defender •
Katherine Martorell (born 1982), Chilean politician •
Katherine Mathieson (born 1975), the director of the Royal Institution •
Katherine Clerk Maxwell (1824–1886), the wife of Scottish physicist James Clerk Maxwell •
Katherine Mayfair, fictional character created by Marc Cherry for the ABC television series Desperate Housewives •
Katherine Mayfield, memoirist, short story writer, poet, and nonfiction author •
Katherine Mayo (1867–1940), American historian and nativist •
Katherine McAlpine (born 1985), American science journalist and rapper •
Katherine McAuliffe, Canadian psychologist •
Katherine Elizabeth McClellan (1859–1934), professional photographer •
Katherine McClure (born 1981), Canadian actress •
Katherine McCoy (born 1945), American graphic designer and educator •
Katherine McFetridge, American rower •
Katherine A. McGlynn, American cancer epidemiologist •
Katherine McGrath (born 1944), American singer and stage and television actress •
Katherine Brunett McGuire, American political aide •
Katherine McHale (born 1955), former American government official •
Katherine McJunkin, American biologist •
Katherine Winthrop McKean (1914–1997), top-ranked American tennis player •
Katherine McKenzie, professor of medicine •
Katherine McKittrick, Canadian professor and academic •
Katherine McLoughlin (1650–1677), successful Irish Quaker preacher •
Katherine McNamara (publisher), writer, editor, and digital publisher in Charlottesville, Virginia •
Katherine McNamara (born 1995), American actress and singer •
Katherine Medina, Colombian model •
Katherine M. Menendez (born 1971), American attorney •
Katherine Merchant (born 1985), English female rugby union player •
Katherine Merrill, American artist •
Katherine Milhous (1894–1977), American artist, illustrator, and writer •
Katherine Miller (born 1994), Brazilian American fencer •
Katherine Mills (born 1983), English magician and mentalist •
Katherine Miranda (born 1986), Colombian political scientist •
Katherine Mirica, American chemist •
Katherine Mitchell (born 1944), American artist •
Katherine Moennig (born 1977), American actress •
Katherine Monaghan (born 1980), British actress •
Katherine Monbiot (1964–1997), English former World Champion armwrestler •
Katherine Monti, American biostatistician •
Katherine Rose Morley (born 1989), English actress •
Katherine Faw Morris (born 1983), American writer •
Katherine Morse, American computer scientist •
Katherine Mortimer, Countess of Warwick (1314–1369), the wife of Thomas de Beauchamp, 11th Earl of Warwick KG •
Katherine Mountain (born 1986), Hong Kong field hockey player •
Katherine Mudge (1881–1975), British archer •
Katherine O. Musgrave (1920–2015), American academic == N ==