William McKinnon Fetzer (June 24, 1884 – May 3, 1959) was an American football, basketball, and baseball coach.

He served as the head football coach at Davidson College (1915–1918), North Carolina State University (1919–1920), and the University of North Carolina at Chapel Hill (1921–1925), compiling a career college football record of 61–28–7.

Fetzer also was the head basketball coach at Davidson for two seasons, from 1916 to 1918, tallying a mark of 18–11.

He made his Major League Baseball (MLB) debut on September 4, 1906 as a pinch hitter for the Philadelphia Athletics.

Prior to his professional career, Fetzer played collegiately at Davidson College.