2021 Halle Open

The 2021 Halle Open (known for sponsorship reasons as the 2021 Noventi Open) was a men's tennis tournament played on outdoor grass courts. It was the 28th edition of the Halle Open and part of the ATP Tour 500 series of the 2021 ATP Tour. It took place at the OWL Arena in Halle, Germany, between 14 June and 20 June 2021. Unseeded Ugo Humbert won the singles title.

Singles

 * 🇫🇷 Ugo Humbert defeated 🇷🇺 Andrey Rublev, 6–3, 7–6(7–4)

Doubles

 * 🇩🇪 Kevin Krawietz / 🇷🇴 Horia Tecău'defeated 🇨🇦 Félix Auger-Aliassime / 🇵🇱 Hubert Hurkacz, 7–6(7–4), 6–4

Prize money

 * per team

Seeds

 * 1 Rankings are as of 31 May 2021.

Other entrants
The following players received wildcards into the main draw:
 * 🇩🇪 Daniel Altmaier
 * 🇩🇪 Philipp Kohlschreiber
 * 🇫🇷 Gaël Monfils
 * Stefanos Tsitsipas

The following player received entry as a special exempt:
 * 🇦🇹 Jurij Rodionov

The following players received entry from the qualifying draw:
 * Nikoloz Basilashvili
 * 🇱🇹 Ričardas Berankis
 * 🇺🇸 Marcos Giron
 * 🇧🇾 Ilya Ivashka
 * 🇸🇰 Lukáš Lacko
 * 🇫🇷 Arthur Rinderknech

The following player received entry as a lucky loser:
 * 🇩🇪 Yannick Hanfmann

Withdrawals

 * Before the tournament
 * 🇪🇸 Pablo Carreño Busta → replaced by 🇫🇷 Corentin Moutet
 * Cristian Garín → replaced by 🇫🇷 Gilles Simon
 * 🇳🇴 Casper Ruud → replaced by 🇺🇸 Sam Querrey
 * Stefanos Tsitsipas → replaced by 🇩🇪 Yannick Hanfmann

Seeds

 * 1 Rankings are as of 31 May 2021.

Other entrants
The following pairs received wildcards into the doubles main draw:
 * 🇩🇪 Daniel Altmaier / Dominic Stricker
 * 🇩🇪 Dustin Brown / 🇩🇪 Jan-Lennard Struff
 * Petros Tsitsipas / Stefanos Tsitsipas

The following pair received entry from the qualifying draw:
 * 🇩🇪 Daniel Masur / 🇩🇪 Rudolf Molleker

The following pair received entry as a lucky loser:
 * 🇩🇪 Yannick Hanfmann / 🇩🇪 Dominik Koepfer

Withdrawals

 * Before the tournament
 * 🇪🇸 Marcel Granollers / 🇦🇷 Horacio Zeballos → replaced by 🇦🇷 Andrés Molteni / 🇦🇷 Guido Pella
 * 🇵🇱 Łukasz Kubot / 🇧🇷 Marcelo Melo → replaced by 🇵🇱 Łukasz Kubot / 🇫🇷 Édouard Roger-Vasselin
 * Petros Tsitsipas / Stefanos Tsitsipas → replaced by 🇩🇪 Yannick Hanfmann / 🇩🇪 Dominik Koepfer