Charles Mayer (7 January 1882 – 5 May 1972) was an American middleweight and heavyweight boxer who competed in the early twentieth century.

In the middleweight category he defeated fellow American Benjamin Spradley in the final to win a gold medal but took silver in the heavier heavyweight category.

Mayer only had to compete in two fights to capture his two medals, in the middleweight class only two boxers participated.

In the heavyweight class there were three boxers with Mayer earning the bye in the first round.

This article about a boxing Olympic medalist of the United States is a stub.