American football •
Bob Williams (1950s American football coach), at Livingston State Teachers College, now University of West Alabama, 1952 •
Bob Williams (coach, born 1877) (1877–1957), American college football coach •
Bob Williams (quarterback) (1930–2016), football player for Notre Dame •
Bobbie Williams (born 1976), American football guard •
Bobby Williams (born 1958), tight end, coach •
Bobby Williams (defensive back) (1942–2012), American pro football player, St. Louis Cardinals and the Detroit Lions •
Robert Williams (defensive back, born 1962), former American football cornerback •
Robert Williams (defensive back, born 1977), former American football cornerback •
Robert Williams (quarterback) ( 1938–1990), football player for Notre Dame, 1956–1958
Baseball •
Bob Williams (baseball) (1884–1962), baseball player for the New York Highlanders/Yankees •
Bobby Williams (baseball) (1895–1978), American baseball shortstop and manager in the Negro leagues •
Robert Williams (baseball) (1917–2000), American baseball pitcher and infielder in the Negro leagues •
Robert Fulton Williams (1917–1999), American baseball pitcher
Basketball •
Bob Williams (basketball, born 1931) (1931–2021), American basketball player, played collegiately at Florida A&M •
Bob Williams (basketball, born 1953), American basketball coach, most recently with UC Santa Barbara •
Rob Williams (basketball) (1961–2014), American basketball player, played collegiately for Houston •
Robert Williams (Grambling State basketball), American college basketball player for Grambling State •
Robert Williams III (born 1997), American basketball player for the Portland Trail Blazers, played collegiately for Texas A&M
Cricket •
Robbie Williams (cricketer) (born 1987), English cricketer for Middlesex •
Robert Williams (English cricketer) (born 1970), English former cricketer •
Robert Williams (South African cricketer) (1912–1984), South African cricketer
Football and rugby •
Bobbie Williams (rugby union) (1865–1967), Welsh international rugby union player •
Bobby Williams (Scottish footballer) (died 1916), Scottish footballer •
Bob Williams (rugby) (1886–1969), Australian rugby league footballer •
Bob Williams (Australian rules footballer) (1913–2004), Australian rules footballer with Hawthorn •
Bobby Williams (footballer, born 1932), English footballer for Chester City •
Bobby Williams (footballer, born 1940), English footballer •
Robbie Williams (footballer, born 1979), English footballer for Warrington Town •
Robbie Williams (footballer, born 1984), English footballer for Limerick •
Robert Williams (footballer, born 1927), English footballer for Wrexham and Shrewsbury Town •
Robert Williams (footballer, born 1932) (1932–2003), English footballer for Mansfield Town
Other sports •
Bob Williams (pole vaulter), American pole vaulter, 1965 All-American for the Maryland Terrapins track and field team •
Bob Williams (rower) (1931–2017), Canadian rower •
Rob Williams (rower, born 1960), British rower •
Rob Williams (rower, born 1985), British Olympian •
Robbie Williams (snooker player) (born 1986), English snooker player •
Robert Williams (archer) (1841–1914), American archer • Robert
Rhyne Williams (born 1991), American tennis player == Other ==