Irwin Untermyer (February 2, 1886 – October 18, 1973) was an American attorney, jurist, and civic leader most notable for his work in New York City.

"It has rarely fallen to the lot of those elected to the bench to have enjoyed the rich experience of Mr. Untermyer," wrote Louis Marshall in The New York Times.

[1] As a result, he had to make oral arguments before the United States Supreme Court in Gilchrist v. Interborough Rapid Transit Company.

[6][1][7] "I am very happy to hear of the decision", then-Congressman Fiorello La Guardia stated, calling Untermyer's argument a "splendid and merited rebuke to the judges who lost their heads in New York and signed the order.

"[9] Among the judges who had “lost their heads” was the notorious Martin T. Manton,[10] who was ultimately revealed to have accepted bribes (in the form of “loans”) from those interested in the case.

[14] He is interred at the Untermyer Family Plot at Woodlawn Cemetery in the Bronx, which features extensive bronzework by Gertrude Vanderbilt Whitney.