

|
| Position | Third Base |
| Team | Los Angeles Dodgers |
| Years of Experience | 10 years |
| Age | 34 |
| Height | 5 ft 10 in (1.78 m) |
| Weight | 180 lb (81.6 kg) |
| Bats | Both |
| Throws | Right |
| College | Southwest Missouri State |
| 2005 Salary | $2,500,000 |
| Place of Birth | Maryland Heights, Missouri |
| Selection | 25th round amateur draft, 1993 amateur |
| Drafted by | San Francisco Giants |
| Major League Debut | April 18, 1996 |
William Richard Mueller [MILL-er] (born March 17, 1971) is a Major League Baseball third baseman who plays for the Los Angeles Dodgers. Previously, Mueller played with the San Francisco Giants (1996-2000, 2002), Chicago Cubs (2001-02) and Boston Red Sox (2003-2005). He is a switch hitter and throws right-handed.
Mueller was born in Maryland Heights, Missouri and attended De Smet Jesuit High School. He was drafted by the Giants in the 1993 amateur draft, and made his debut in 1996. He was traded to the Cubs before the 2001 season, and returned to San Francisco in September 2002. Before the 2003 season, Mueller was signed by the Red Sox as a free agent. In his first year in Boston he won the American League batting title with a .326 average.
In a ten-year career, Mueller is a .292 hitter with 82 home runs and 478 RBI in 1184 games.