| Birth Date: | 4 March 1909 |
| Birth Place: | Storvik, Sweden |
| Death Date: | 30 September 1995 (aged 86) |
| Death Place: | Göteborg, Sweden |
| Height: | 1.88m (06.17feet) |
| Weight: | 78kg (172lb) |
| Sport: | Athletics |
| Event: | 400 m |
| Club: | IF Thor, Uppsala; IK Göta |
| Pb: | 400 m – 47.8 (1937) |
| Show-Medals: | yes |
Johan Bertil Karl von Wachenfeldt (4 March 1909 – 30 September 1995) was a Swedish sprinter who specialized in the 400 m distance. He competed in the 4 × 400 m relay at the 1928 and 1936 Summer Olympics and finished in fourth and fifth place, respectively; in 1936 he failed to reach the final of the individual 400 m event.
Wachenfeldt won three bronze medals at the European championships: two in 1934 and one in 1938. He won the national 400 m title in 1935 and 1938 and held the national records over 300 m and 400 m.