Flyweight
| Number | Champion | Reign |
|---|---|---|
| 1 | Pancho Villa | June 18, 1923 - September 24, 1925 |
| 2 | Fidel LaBarba (Defeated Elky Clark) | January 21, 1927 - August 23, 1927 (Retired) |
| 3 | Benny Lynch (Defeated Small Montana) | January 19, 1937 - June 29, 1938 (Vacated/Missed weight) |
| 4 | Peter Kane (Defeated Jackie Jurich) | September 22, 1938 - June 19, 1943 |
| 5 | Jackie Paterson | June 19, 1943 - March 23, 1948 |
| 6 | Rinty Monaghan | March 23, 1948 - April 25, 1950 (Retired) |
| 7 | Terry Allen (Defeated Honore Pratesi) | April 25, 1950 - August 1, 1950 |
| 8 | Dado Marino | August 1, 1950 - May 19, 1952 |
| 9 | Yoshio Shirai | May 19, 1952 - November 26, 1954 |
| 10 | Pascual Perez | November 26, 1954 - April 16, 1960 |
| 11 | Pone Kingpetch | April 16, 1960 - October 10, 1962 |
| 12 | Fighting Harada | October 10, 1962 - January 12, 1963 |
| 13 | Pone Kingpetch | January 12, 1963 - September 18, 1963 |
| 14 | Hiroyuki Ebihara | September 18, 1963 - January 23, 1964 |
| 15 | Pone Kingpetch | January 23, 1964 - April 23, 1965 |
| 16 | Salvatore Burruni | April 23, 1965 - June 14, 1966 |
| 17 | Walter McGowan | June 14, 1966 - December 30, 1966 |
| 18 | Chartchai Chionoi | December 30, 1966 - February 23, 1969 |
| 19 | Efren Torres | February 23, 1969 - March 20, 1970 |
| 20 | Chartchai Chionoi | March 20, 1970 - December 7, 1970 |
| 21 | Erbito Salavarria | December 7, 1970 - February 9, 1973 |
| 22 | Venice Borkorsor | February 9, 1973 - July 10, 1973 (Vacated/Moved to Bantamweight) |
| 23 | Miguel Canto (Defeated Shoji Oguma) | January 8, 1975 - March 18, 1979 |
| 24 | Chan-Hee Park | March 18, 1979 - May 18, 1980 |
| 25 | Shoji Oguma | May 18, 1980 - May 12, 1981 |
| 26 | Antonio Avelar | May 12, 1981 - March 20, 1982 |
| 27 | Prudencio Cardona | March 20, 1982 - July 24, 1982 |
| 28 | Freddy Castillo | July 24, 1982 - November 6, 1982 |
| 29 | Eleoncio Mercedes | November 6, 1982 - March 15, 1983 |
| 30 | Charlie Magri | March 15, 1983 - September 27, 1983 |
| 31 | Frank Cedeno | September 27, 1983 - January 18, 1984 |
| 32 | Koji Kobayashi | January 18, 1984 - April 9, 1984 |
| 33 | Gabriel Bernal | April 9, 1984 - October 8, 1984 |
| 34 | Sot Chitalada | October 8, 1984 - July 24, 1988 |
| 35 | Yong-Kang Kim | July 24, 1988 - March 2, 1989 (The Ring ceased awarding belts) |
| 36 | Pongsaklek Wonjongkam (Defeated Kōki Kameda) | March 27, 2010 – March 2, 2012 |
| 37 | Sonny Boy Jaro | March 2, 2012 – July 16, 2012 |
| 38 | Toshiyuki Igarashi | July 16, 2012 - present |
Read more about this topic: List Of The Ring World Champions