Julian Lenz
Julian Lenz is a German tennis player. He won the 2011 US Open boys' doubles title, partnering Robin Kern. He has an ATP career high singles ranking of world No. 227, achieved in January 2020. In doubles, he reached his career-high ranking of No. 207 in February 2020.
Lenz played college tennis for the Baylor University.
He made his ATP Tour main draw debut by qualifying for both singles and doubles at the 2019 Hamburg European Open. In singles, he lost to world No. 10 Fabio Fognini in the first round. In doubles, he and partner Daniel Masur upset compatriots Alexander and Mischa Zverev after saving two match points in the opening round.
Junior Grand Slam finals
Doubles: 1 (1 title)
ATP Challenger and ITF Futures finals
Singles: 8 (3–5)
| Result | W–L | Date | Tournament | Tier | Surface | Opponent | Score |
| Loss | 0–1 | Wetzlar, Germany | Futures | Clay |  Bastian Knittel | 2–6, 6–3, 3–6 | |
| Loss | 0–2 | Wetzlar, Germany | Futures | Clay |  Evgeny Korolev | 0–6, 6–0, 3–6 | |
| Loss | 0–3 | Plantation, United States | Futures | Clay |  Christian Lindell | 5–7, 0–6 | |
| Loss | 0–4 | Kassel, Germany | Futures | Clay | Yannick Hanfmann | 6–7, 1–6 | |
| Win | 1–4 | Prague, Czech Republic | Futures | Clay |  Juraj Masár | 6–2, 6–3 | |
| Win | 2–4 | Most, Czech Republic | Futures | Clay |  Jan Mertl | 4–6, 6–2, 6–2 | |
| Loss | 2–5 | Hong Kong, China | Futures | Hard |  Evan Furness | 5–6, ret. | |
| Win | 3–5 | Karlsruhe, Germany | Futures | Clay |  Andrea Pellegrino | 6–3, 6–7, 6–3 |
Doubles: 10 (4–6)
| Result | W–L | Date | Tournament | Tier | Surface | Partner | Opponents | Score |
| Loss | 0–1 | Wetzlar, Germany | Futures | Clay | Lars Pörschke |  Wesley Koolhof Rogier Wassen | 6–3, 0–6, | |
| Loss | 0–2 | Wetzlar, Germany | Futures | Clay | Lars Pörschke | David Pel Dennis van Scheppingen | 6–7, 6–7 | |
| Loss | 0–3 | Waco, United States | Futures | Hard |  William Little | Sekou Bangoura Matt Seeberger | 6–1, 3–6, | |
| Win | 1–3 | Saarlouis, Germany | Futures | Clay | Sebastian Fanselow |  Marcel Felder Manuel Peña López | 7–6, 6–3 | |
| Loss | 1–4 | Waco, United States | Futures | Hard |  Juan Manuel Benitez |  Farris Fathi Gosea Hans Hach Verdugo | 5–7, 3–6 | |
| Win | 2–4 | Niceville, United States | Futures | Clay | Juan Manuel Benitez |  Boris Arias Nick Chappell | 7–5, 4–6, | |
| Win | 3–4 | Waco, United States | Futures | Hard |  Roberto Maytín | Nathaniel Lammons Alex Lawson | 7–6, 1–6, | |
| Win | 4–4 | Trento, Italy | Futures | Hard |  Alexander Erler | Felix Corwin Danny Thomas | 6–3, 6–4 | |
| Loss | 4–5 | Kazan, Russia | Futures | Hard | Jeremy Jahn |  Konstantin Kravchuk Alexander Pavlioutchenkov | walkover | |
| Loss | 0–1 | 2020 Koblenz Open – Doubles| | Koblenz, Germany | Challenger | Hard | Yannick Maden | Sander Arends David Pel | 6–7, 6–7 |