William Frank Southall (2 July 1904 – 1 March 1964) was an English racing cyclist who won silver medals for Great Britain in the individual road race (run as an individual time trial) at the 1928 Summer Olympics and a track cycling medal at the 1932 Summer Olympics in Los Angeles.

He rode for the South London Norwood Paragon cycling club, broke numerous time trial and Road Records Association place-to-place records in domestic competitions, winning the first four British Best All-Rounder (BBAR) competitions from 1930 to 1933.

Southall was selected by the National Cyclists' Union to represent Britain at the 1926 UCI Road World Championships, where he finished in eighth place.

[6] In 1933, Southall and Stan Butler rode the Oak Tandem 100, winning in 4h 1m 3s, beating the record by two minutes.

[7] The Olympic road race in Amsterdam in 1928 was run against the clock, as an individual time-trial.

Southall was one of the best performers in the world against the clock but in 21 miles (34 km) he lost seven minutes to Henry Hansen of Denmark.

[9] Southall finished sixth in the Olympic road race in 1932, with Charles Holland 15th and Stan Butler 16th.

In 1935, a team of Australian cyclists, including Hubert Opperman 'Hefty' Stuart and Ern Milliken traveled to England to attack various distance records.

[15] Southall responded with four unsuccessful attempts to regain the London-Brighton-London record before he succeeded in a time of 4h 38' 27".