William Reuben "Billy" Tremelling (May 9, 1905 — 1961) was an English professional footballer. He played as a forward at the beginning of his career, but was later played as a defender. He was the younger brother of fellow footballer Dan Tremelling, a goalkeeper who played for England.
Tremelling made his debut for Blackpool on March 28, 1925, in a goalless draw at Manchester United in front of a crowd of 30,000. He made one more league appearance in 1924–25 season, in the very next game (a home victory over Southampton), but missed the final eight games of the season.
He made a major impact in 1926–27, with 30 goals in 26 league games. He scored his first goal for Blackpool on November 13, 1926, in a 3–0 victory over Bradford City at Bloomfield Road. He went on to score in the next five games, including a hat-trick in a 6–0 home victory over Clapton Orient on December 11. He scored another treble in a 4–2 victory at Port Vale on April 16, 1927, the second of Blackpool's two games in as many days. Tremelling also scored Blackpool's sole goal in the FA Cup that season, in a 3–1 third-round loss at home to Bolton Wanderers on January 8, 1927.
In 1927–28, Tremelling, under new Blackpool boss Sydney Beaumont, was switched to a defensive position. As such, his goal hauls dried up: he made 22 appearances and scored just four goals that season.
Back in a defensive role for the 1929–30 campaign, Tremelling helped Blackpool to the Division Two championship. He made 38 league appearances and scored three goals in the club's successful season.
After retirement, Tremelling returned to Blackpool as a coach.