Said to be originally Maynoers, Meyners, then Menys afterward Meynes or Mengies, and now Menzies--a branch of the family of Manners, in England, the name being originally the same. I think, rather, the name is derived from the parish of Monzie, in Perthshire, Scotland.

Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.

MENZIES. The Menzles, though sometimes considered a Highland clan, are of English origin. Their name was originally Meyners, and as Skene observes, (Scot, Highl. ii. 310) "their arms, and the resemblance of their name, distinctly point them out as a branch of the English family of Manners, and consequently their Norman origin is undoubted." 2. The name, according to Mr. Arthur, has been variously written, " Maynoers, Meyners, then Men.ys, afterwards Jleynes or Mengies, and now Menzies." It is pronounced Mengyies or Mengies. In Gaelic the family are called MenairieJi. Their habitat is the Perthshire Highlands, where in ITl. the clan could raise three hundred fighting men.

Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.