The 2021 Sparkassen Open was a professional tennis tournament played on clay courts. It was the 27th edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Braunschweig, Germany between 5 and 11 July 2021.
Singles main-draw entrants
Seeds
1 Rankings are as of 28 June 2021.
Other entrants
The following players received wildcards into the singles main draw: Rudolf Molleker Marvin Möller Benoît Paire
The following players received entry into the singles main draw as alternates: Malek Jaziri Mischa Zverev
The following players received entry from the qualifying draw: Sandro Ehrat Dayne Kelly Daniel Michalski Mats Rosenkranz
The following player received entry as a lucky loser: Benjamin Hassan
Champions
Singles
Daniel Altmaier def. Henri Laaksonen 6–1, 6–2.
Doubles
Szymon Walków / Jan Zieliński def. Ivan Sabanov / Matej Sabanov 6–4, 4–6, [10–4].