Frank R. Gaynor (September 2, 1852 – August 2, 1920) was a justice of the Iowa Supreme Court from January 1, 1913, to August 2, 1920, appointed from Plymouth County.

Frank R. Gaynor was born in Hamilton, Canada West, on September 2, 1852.

[1][2] He earned a law degree from the State University of Iowa in 1877.

[1][3] He married Anna C. Judd in Iowa City on November 29, 1887.

[1] Frank R. Gaynor died from heart disease at his home in Des Moines on August 2, 1920.