Clarence Joseph Diebold (August 1, 1881 – January 1964) was an American football player from Pittsburgh, Pennsylvania and a starting quarterback for the University of Notre Dame. Diebold earned the starting quarterback job at the turn of the century under new head coach Pat O'Dea. His team began the season in magnificent fashion, outscoring their first four opponents by a combined total of 245-0. However, the run skidded to a halt with a 0-6 loss at Indiana, followed by a 6-6 tie against Beloit and a demoralizing 0-54 loss at Wisconsin—the worst-ever loss for the Irish at that time. But the team showed spirit in a competitive 0-7 loss at Michigan, then closed out the year with two straight wins for a final record of 6-3-1.