2021 Lisboa Belém Open – Men's doubles
# 2021 Lisboa Belém Open – Men's doubles

Roberto Cid Subervi and Gonçalo Oliveira were the defending champions but only Oliveira chose to defend his title, partnering Andrej Martin. Oliveira withdrew before the start of the tournament due to an injury.

Jeevan Nedunchezhiyan and Purav Raja won the title after defeating Nuno Borges and Francisco Cabral $7–6^{(7–5)},$ 6–3 in the final.

## Seeds

* Jeevan Nedunchezhiyan / Purav Raja (champions)
* Marco Bortolotti / Andrea Pellegrino (quarterfinals)
* Andrej Martin / Gonçalo Oliveira (withdrew)
* Sadio Doumbia / Hugo Gaston (withdrew)

## Draw

### Key

* Q = Qualifier
* WC = Wild card
* LL = Lucky loser
* Alt = Alternate
* SE = Special exempt
* PR = Protected ranking
* ITF = ITF entry
* JE = Junior exempt
* w/o = Walkover
* r = Retired
* d = Defaulted
* SR = Special ranking

| First round | First round | First round | First round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final |
| - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| 1 | J Nedunchezhiyan P Raja | 6 | 6 | | | | | | | | | | | | | |
| WC | T Cação Gonçalo Falcão | 3 | 2 | 1 | J Nedunchezhiyan P Raja | 6 | 6 | | | | | | | | | |
| | L Patiño S Rodríguez Taverna | 4 | 3 | | F Forti G Zeppieri | 3 | 4 | | | | | | | | | |
| | F Forti G Zeppieri | 6 | 6 | | | | | 1 | J Nedunchezhiyan P Raja | 4 | 6 | [10] | | | | |
| | | | | | | | | WC | J Faria L Faria | 6 | 3 | [5] | | | | |
| WC | Jaime Faria Luís Faria | 6 | 6 | WC | J Faria L Faria | | | | | | | | | | | |
| | I Sijsling G Smits | 4 | 3 | | | | | | | | | | 1 | J Nedunchezhiyan P Raja | $7^7$ | 6 |
| WC | Miguel Gomes H Rocha | 3 | 3 | | | | | | | | | | | N Borges F Cabral | $6^5$ | 3 |
| | N Borges F Cabral | 6 | 6 | | N Borges F Cabral | 6 | 6 | | | | | | | | | |
| | M Geerts M Vervoort | 3 | 2 | Alt | S Fanselow L Gerch | 4 | 4 | | | | | | | | | |
| Alt | Sebastian Fanselow Lucas Gerch | 6 | 6 | | | | | | N Borges F Cabral | 6 | 6 | | | | | |
| | T Lamasine A Müller | $6^{11}$ | 2 | | | | | | F Fallert P Heller | 2 | 2 | | | | | |
| | F Fallert Peter Heller | $7^{13}$ | 6 | | F Fallert P Heller | 6 | 6 | | | | | | | | | |
| | B Bobrov K Uchida | $6^4$ | 4 | 2 | M Bortolotti A Pellegrino | 1 | 2 | | | | | | | | | |
| 2 | M Bortolotti A Pellegrino | $7^7$ | 6 | | | | | | | | | | | | | |
