Charles A. Armbruster (August 30, 1880 - October 7, 1964) was a backup catcher in Major League Baseball who played with the Boston Red Sox (1905-1907) and Chicago White Sox (1907). He batted and threw right handed.
A native of Cincinnati, Ohio, Ambruster shared catching duties with Lou Criger for the Red Sox in part of three seasons. In 1906 he appeared in a career-high 72 games and hit .144 (21-for-201)
In a three-year career, Ambruster was a .149 hitter (53-for-355) with 24 runs and 12 RBI in 131 games
Ambruster died in Grants Pass, Oregon at the age of 84.