David Mercer (born 16 April 1961 in Salford, United Kingdom) is a weightlifter from Great Britain.
He competed for Great Britain in the 1984 Summer Olympics held in Los Angeles, United States in the Middle-heavyweight (90 kg) event where (in the absence of the boycotting Soviet nations) he finished in third place. Four years later he competed at the 1988 Summer Olympics in Seoul but was unable to win a second medal, finishing in sixth place.