Dennis James Sommers (born July 12, 1940, at New London, Wisconsin) is a retired American professional baseball catcher, manager and coach. A left-handed batter who threw right-handed, Sommers stood 6 feet 2 inches (1.88 m) tall and weighed 205 pounds (93 kg). He is the brother of Tom Sommers, a former minor league infielder and manager, and one-time player development director of the California Angels.
Dennis Sommers spent the first 18 years of his baseball career as a player and manager in the San Francisco Giants' farm system, peaking for two half seasons (1965–1966) with the Tacoma Giants and Phoenix Giants of the Triple-A Pacific Coast League. Later in 1966, he began his managerial career as a midseason replacement for the Lexington Giants of the Class A Western Carolinas League. He handled San Francisco farm teams through 1975, ending as the team's Double-A skipper. His 1975 Lafayette Drillers were co-champions of the Texas League.
After spending the 1976 campaign as pilot of the Chicago Cubs' Midland Cubs TL affiliate, Sommers came to Major League Baseball for the first time as bullpen coach of the New York Mets in 1977–1978, working for Joe Frazier and Joe Torre. When his contract was not renewed for 1979, Sommers moved to the Detroit Tigers' system as manager of the Montgomery Rebels of the Double-A Southern League.
Then, in 1980, Sommers returned to MLB as a coach for the Cleveland Indians (1980–1985). He later coached for the San Diego Padres (1988–1990) and the Giants (1993–1994). In between those assignments, he served as a minor league instructor, scout, and front-office official. All told, Sommers coached in Major League Baseball for 13 seasons.