Leyton Orient played 185 league seasons and cup tournaments in the data, 1906 to 2026. Success weighs every finish by how hard that competition was to win; Efficiency is the share of what the club could have won that it did win; Edge compares that with an average participant (×1.00).
| 521 | Ascoli (Italy) | 5.4 |
| 522 | Brasil de Pelotas (Brazil) | 5.4 |
| 523 | Tavria Simferopol (Ukraine) | 5.4 |
| 524 | Leyton Orient (England) | 5.4 |
| 525 | Portimonense SC (Portugal) | 5.3 |
| 526 | Arbroath (Scotland) | 5.3 |
| 527 | Fortuna Sittard (Netherlands) | 5.3 |