2021 Belgrade Challenger – Men's doubles
| Men's doubles | |
|---|---|
| 2021 Belgrade Challenger | |
| Champions | Guillermo Durán Andrés Molteni |
| Runners-up | Tomislav Brkić Nikola Ćaćić |
| Score | 6–4, 6–4 |
This was the first of the three tournaments held in Belgrade for the 2021 tennis season. Belgrade also hosted a joint ATP/WTA tournament.
Guillermo Durán and Andrés Molteni won the title after defeating Tomislav Brkić and Nikola Ćaćić 6–4, 6–4 in the final.