There are two groups using this name.
1) Originally known as The Little Williams Brothers, The Williams Brothers are a gospel music trio, founded by their father Leon "Pop" Williams in 1960. They have recorded 18 albums, starting in 1973. The current group is Doug Williams, Melvin Williams, and Henry Green 2) Andrew and David Williams, identical twins and nephews of Andy Williams, recorded three albums as The Williams Brothers in the 1980s and 90s. They first appeared as guest stars on The Partridge Family TV show in 1974 at age 14, and recorded as Andy & David Williams at the time.