2021 Lisboa Belém Open

The 2021 Lisboa Belém Open was a professional tennis tournament played on outdoor clay courts. It was the fifth (men) and first (women) editions of the tournament which were part of the 2021 ATP Challenger Tour and the 2021 ITF Women's World Tennis Tour. It took place in Lisbon, Portugal between 27 September and 3 October 2021.

Seeds

 * 1 Rankings are as of 20 September 2021.

Other entrants
The following players received wildcards into the singles main draw:
 * Pedro Araújo
 * Tiago Cação
 * Gonçalo Oliveira

The following player received entry into the singles main draw using a protected ranking:
 * 🇲🇦 Elliot Benchetrit

The following players received entry from the qualifying draw:
 * 🇩🇪 Sebastian Fanselow
 * 🇩🇪 Benjamin Hassan
 * 🇵🇱 Daniel Michalski
 * 🇦🇷 Santiago Rodríguez Taverna

The following player received entry as a lucky loser:
 * 🇮🇹 Jacopo Berrettini

Seeds

 * 1 Rankings are as of 20 September 2021.

Other entrants
The following players received wildcards into the singles main draw:
 * Carolina Azadinho
 * Matilde Morais
 * Sofia Pinto
 * Ana Filipa Santos

The following players received entry from the qualifying draw:
 * 🇮🇹 Nuria Brancaccio
 * 🇪🇸 Ángela Fita Boluda
 * 🇮🇹 Nicole Fossa Huergo
 * 🇳🇴 Malene Helgø
 * 🇰🇷 Ku Yeon-woo
 * 🇹🇷 İpek Öz
 * 🇺🇦 Ganna Poznikhirenko
 * 🇷🇴 Andreea Prisăcariu

Men's singles

 * 🇰🇿 Dmitry Popko def. 🇮🇹 Andrea Pellegrino 6–2, 6–4.

Women's singles

 * 🇪🇸 Irene Burillo Escorihuela def. 🇹🇷 İpek Öz, 6–4, 6–0

Men's doubles

 * 🇮🇳 Jeevan Nedunchezhiyan / 🇮🇳 Purav Raja def. Nuno Borges /  Francisco Cabral 7–6(7–5), 6–3.

Women's doubles

 * 🇪🇸 Yvonne Cavallé Reimers / 🇪🇸 Ángela Fita Boluda def. 🇦🇷 Paula Ormaechea / 🇷🇸 Natalija Stevanović, 3–6, 6–3, [10–4]