| Leni Junker | |
| Fullname: | Helene Junker |
| Birth Date: | 8 December 1905 |
| Birth Place: | Kassel, Germany |
| Death Date: | 9 February 1997 (aged 91) |
| Death Place: | Wilhelmshaven, Germany |
| Height: | 1.68m (05.51feet) |
| Weight: | 68kg (150lb) |
| Sport: | Running |
| Club: | Kasseler Turngemeinde |
| Show-Medals: | yes |
Helene "Leni" Junker (later Thymm; 8 December 1905 – 9 February 1997) was a German sprint runner who competed at the 1928 Summer Olympics. She won a bronze medal in the 4 × 100 m, but failed to reach the final of the individual 100 m event. Earlier in 1925 she set a world record in the 100-metre at 12.2 seconds.