Robert Reasoner Nevin (2 August 1875, in Dayton, Ohio – 31 December 1952) was a United States federal judge. He attended Ohio State University and Cincinnati Law School, but read law to enter the bar in 1898. He served as a Lieutenant in the United States Army during the Spanish–American War, and was in private practice in Dayton, Ohio from 1898 to 1903. He was a Prosecuting attorney of Montgomery County, Ohio from 1906 to 1919.
On January 5, 1929, Nevin was nominated by President Calvin Coolidge to a seat on the United States District Court for the Southern District of Ohio vacated by Smith Hickenlooper. Nevin was confirmed by the United States Senate on January 21, 1929, and received his commission the same day. He served as chief judge from 1948 until his death on December 31, 1952.