John A. Gaynor (October 1, 1846 – May 12, 1915) was an American businessman, jurist, and politician.
Born in County Longford, Ireland, Gaynor emigrated with his parents to the United States in 1851 and settled in the town of Lisbon, Waukesha County, Wisconsin.
Gaynor graduated from University of Wisconsin and then taught school.
Gaynor also served on the Wisconsin Common Council and the school board.
This article about a Democratic Party member of the Wisconsin State Assembly is a stub.