John Hardin Oldham (November 6, 1932 – February 24, 2024) was an American Major League Baseball player.

In 1955, he pitched for the Seattle Rainiers of the Pacific Coast League, where he had a record of 9–6 and an earned run average of 3.84.

[3] Despite not appearing in a single minor league game in 1956 (due to an injury), the Redlegs called Oldham up in September.

On September 2, 1956, he entered the game against the Chicago Cubs in the third inning at Crosley Field in Cincinnati as a pinch runner for Ted Kluszewski, who himself had pinch-hit for third baseman Alex Grammas.

From 1985 to 1997, Oldham coached the Broncos of Santa Clara University, leading them to four NCAA appearances and three West Coast Conference championships.