2021 ATP Lyon Open

The 2021 ATP Lyon Open (also known as the Open Parc Auvergne-Rhône-Alpes Lyon) was a men's tennis tournament played on outdoor clay courts. It was the fourth edition of the Lyon Open and part of the ATP Tour 250 series of the 2021 ATP Tour. It took place in the city of Lyon, France, from 15 May through 22 May 2021. Second-seeded Stefanos Tsitsipas won the singles title.

Singles

 * Stefanos Tsitsipas defeated 🇬🇧 Cameron Norrie, 6–3, 6–3

Doubles

 * Hugo Nys / 🇩🇪 Tim Pütz defeated 🇫🇷 Pierre-Hugues Herbert / 🇫🇷 Nicolas Mahut, 6–4, 5–7, [10–8]

Prize money

 * per team

Seeds

 * Rankings are as of May 10, 2021.

Other entrants
The following players received wildcards into the singles main draw:
 * 🇫🇷 Benjamin Bonzi
 * 🇦🇹 Dominic Thiem
 * Stefanos Tsitsipas

The following player received entry as an alternate:
 * 🇮🇹 Lorenzo Musetti

The following players received entry from the qualifying draw:
 * 🇫🇷 Grégoire Barrère
 * 🇵🇱 Kamil Majchrzak
 * João Sousa
 * 🇸🇪 Mikael Ymer

The following players received entry as lucky losers:
 * 🇫🇷 Arthur Rinderknech
 * 🇧🇷 Thiago Seyboth Wild

Withdrawals

 * Before the tournament
 * 🇮🇹 Matteo Berrettini → replaced by 🇫🇷 Corentin Moutet
 * 🇫🇷 Jérémy Chardy → replaced by 🇯🇵 Yoshihito Nishioka
 * 🇬🇧 Dan Evans → replaced by 🇫🇷 Pierre-Hugues Herbert
 * 🇺🇸 Taylor Fritz → replaced by 🇬🇧 Cameron Norrie
 * Lloyd Harris → replaced by 🇧🇷 Thiago Seyboth Wild
 * 🇦🇺 John Millman → replaced by 🇫🇷 Gilles Simon
 * 🇪🇸 Albert Ramos Viñolas → replaced by 🇫🇷 Arthur Rinderknech
 * 🇮🇹 Lorenzo Sonego → replaced by 🇮🇹 Lorenzo Musetti

Seeds

 * Rankings are as of May 10, 2021.

Other entrants
The following pairs received wildcards into the doubles main draw: The following pair enters with a protected ranking into the doubles main draw:
 * 🇫🇷 Grégoire Barrère / 🇫🇷 Albano Olivetti
 * Petros Tsitsipas / Stefanos Tsitsipas
 * 🇪🇸 Marc López / 🇫🇷 Fabrice Martin

Withdrawals

 * Before the tournament
 * 🇫🇷 Jérémy Chardy / 🇫🇷 Fabrice Martin → replaced by 🇪🇸 Marc López / 🇫🇷 Fabrice Martin
 * 🇳🇿 Marcus Daniell / 🇦🇹 Philipp Oswald → replaced by 🇸🇪 André Göransson / 🇧🇾 Andrei Vasilevski
 * 🇮🇱 Jonathan Erlich / Lloyd Harris → replaced by 🇳🇿 Artem Sitak /  João Sousa
 * 🇦🇺 John Millman / 🇮🇳 Divij Sharan → replaced by Sander Arends / 🇮🇳 Divij Sharan
 * 🇵🇰 Aisam-ul-Haq Qureshi / 🇮🇹 Andrea Vavassori → replaced by 🇰🇿 Aleksandr Nedovyesov / 🇮🇹 Andrea Vavassori