2021 Ostrava Challenger

The 2021 Ostrava Challenger was a professional tennis tournament played on clay courts. It was the 18th edition of the tournament which was part of the 2021 ATP Challenger Tour. It took place in Ostrava, Czech Republic between 26 April and 2 May.

Seeds

 * 1 Rankings are as of 19 April 2021.

Other entrants
The following players received wildcards into the singles main draw:
 * 🇨🇿 Martin Krumich
 * 🇨🇿 Jiří Lehečka
 * 🇨🇿 Patrik Rikl

The following player received entry into the singles main draw as an alternate:
 * Marcelo Tomás Barrios Vera

The following players received entry from the qualifying draw:
 * 🇸🇰 Lukáš Klein
 * 🇦🇹 Lucas Miedler
 * 🇸🇰 Alex Molčan
 * 🇩🇪 Oscar Otte

Singles

 * 🇫🇷 Benjamin Bonzi def. 🇦🇷 Renzo Olivo 6–4, 6–4.

Doubles

 * 🇦🇺 Marc Polmans / 🇺🇦 Sergiy Stakhovsky def. 🇨🇿 Andrew Paulson / 🇨🇿 Patrik Rikl 7–6(7–4), 3–6, [10–7].