Constantin Frantzen
| Country (sports) | Germany |
|---|---|
| Born | 16 March 1998 Düsseldorf, Germany |
| Height | 1.93 m (6 ft 4 in) |
| Plays | Right-handed (two-handed backhand) |
| College | Baylor University |
| Prize money | US $654,637 |
| Singles | |
| Career record | 0–0 |
| Career titles | 0 |
| Highest ranking | No. 1,226 (20 February 2023) |
| Doubles | |
| Career record | 54–54 |
| Career titles | 1 |
| Highest ranking | No. 35 (23 February 2026) |
| Current ranking | No. 35 (23 February 2026) |
| Grand Slam doubles results | |
| Australian Open | 1R (2024, 2025, 2026) |
| French Open | 2R (2025) |
| Wimbledon | QF (2024) |
| US Open | QF (2025) |
| Last updated on: 23 February 2026. | |
Constantin Frantzen (born 16 March 1998) is a German professional tennis player who specializes in doubles. He has a career-high ATP doubles ranking of world No. 35 achieved on 23 February 2026.
Frantzen has won one ATP Tour doubles title at the 2025 Chengdu Open, with Robin Haase.
He played college tennis at Baylor University.