As coach Robert Daniel Didier (born February 16, 1949) is an American former catcher in Major League Baseball who played for three different teams from 1969 through 1974.

He entered the majors in 1969 with the Atlanta Braves, playing with them four years before joining the Detroit Tigers (1973) and Boston Red Sox (1974).

In his rookie season, Didier appeared in a career-high 114 games, helping his team win the National League West Division title.

In the majors, he has coached for the Oakland Athletics (1984–86) and Seattle Mariners (1989–90), and also has worked as a catching coordinator in the Arizona Diamondbacks system.

In 2007 Didier was part of the coaching staff at Major League Baseball's Academy in Tirrenia, Italy.