2021 Sibiu Open

The 2021 Sibiu Open was a professional tennis tournament played on clay courts. It was the tenth edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Sibiu, Romania between 27 September and 3 October 2021.

Singles main-draw entrants

Seeds

¹ Rankings are as of 20 September 2021.
Other entrants

The following players received wildcards into the singles main draw:

The following players received entry from the qualifying draw:

Yan Bondarevskiy
David Ionel
Yshai Oliel
Ștefan Paloși

The following player received entry as a lucky loser:

Elmar Ejupovic
Champions

Singles

Stefano Travaglia def. Thanasi Kokkinakis 7–6, 6–2.
Doubles
Alexander Erler / Lucas Miedler def. James Cerretani / Luca Margaroli 6–3, 6–1.