| Doubles | |
|---|---|
| 2018 Estoril Open | |
| Champions |  Kyle Edmund Cameron Norrie |
| Runners-up |  Wesley Koolhof  Artem Sitak |
| Score | 6–4, 6–2 |
Ryan Harrison and Michael Venus were the defending champions, [1] but Harrison chose not to participate this year. Venus played alongside Raven Klaasen, but lost in the first round to Alex de Minaur and Lleyton Hewitt.
Kyle Edmund and Cameron Norrie won the title, defeating Wesley Koolhof and Artem Sitak in the final, 6–4, 6–2.
John Peers / Jean-Julien Rojer (quarterfinals)
Raven Klaasen / Michael Venus (first round)
Marc López / David Marrero (first round)
Marcelo Demoliner / 
Santiago González (first round)| First round | Quarterfinals | Semifinals | Final | ||||||||||||||||||||||||
| 1 | J Peers J-J Rojer | 6 | 77 | ||||||||||||||||||||||||
 G Durán A Molteni | 2 | 62 | 1 | J Peers J-J Rojer | 4 | 64 | |||||||||||||||||||||
 J Eysseric J Salisbury | 6 | 3 | [10] | J Eysseric J Salisbury | 6 | 77 | |||||||||||||||||||||
S Arends  A Shamasdin | 3 | 6 | [6] | J Eysseric J Salisbury | 5 | 3 | |||||||||||||||||||||
| 3 | M López D Marrero | 77 | 4 | [3] | W Koolhof A Sitak | 7 | 6 | ||||||||||||||||||||
| W Koolhof A Sitak | 65 | 6 | [10] | W Koolhof A Sitak | 77 | 4 | [10] | ||||||||||||||||||||
 J Erlich  S Lipsky | 6 | 2 | [9] | WC |  G Elias P Sousa | 62 | 6 | [8] | |||||||||||||||||||
| WC | G Elias P Sousa | 2 | 6 | [11] | W Koolhof A Sitak | 4 | 2 | ||||||||||||||||||||
| L Mayer J Sousa | 6 | 77 | K Edmund C Norrie | 6 | 6 | ||||||||||||||||||||||
 A Behar MÁ Reyes-Varela | 4 | 64 | L Mayer J Sousa | 6 | 6 | ||||||||||||||||||||||
| R Haase M Middelkoop | 6 | 6 | R Haase M Middelkoop | 2 | 4 | ||||||||||||||||||||||
| 4 | M Demoliner S González | 4 | 4 | L Mayer J Sousa | 2 | 64 | |||||||||||||||||||||
| F Delbonis N Kicker | 4 | 0 | K Edmund C Norrie | 6 | 77 | ||||||||||||||||||||||
| K Edmund C Norrie | 6 | 6 | K Edmund C Norrie | 6 | 77 | ||||||||||||||||||||||
| WC | A de Minaur L Hewitt | 6 | 6 | WC | A de Minaur L Hewitt | 4 | 64 | ||||||||||||||||||||
| 2 | R Klaasen M Venus | 4 | 4 | ||||||||||||||||||||||||
Johan Brunström and Frederik Nielsen were the defending champions, but Nielsen chose not to participate. Brunström played alongside Nicholas Monroe, but lost in the first round to Roberto Bautista Agut and Stan Wawrinka.
Lu Yen-hsun and Jonathan Marray won the title, defeating Raven Klaasen and Leander Paes in the final, 6–3, 7-6(7–4).
Raven Klaasen and Leander Paes were the defending champions, but Klaasen chose not to compete this year and Paes chose to participate in Sydney instead.
Ivo Karlović and Łukasz Kubot were the defending champions, but Karlović chose not to participate this year and Kubot chose to compete in Stuttgart instead.
Mate Pavić and Michael Venus won the title, defeating Dominic Inglot and Raven Klaasen in the final, 3–6, 6–3, [11–9].
Ryan Harrison and Michael Venus won the men's doubles tennis title at the 2017 French Open, defeating Santiago González and Donald Young in the final, 7–6(7–5), 6–7(4–7), 6–3. In a rare coincidence, none of the four players had ever previously appeared in the men's doubles finals of a Grand Slam tournament prior to the event.
Raven Klaasen and Rajeev Ram were the defending champions, but Klaasen chose not to participate this year and Ram chose to compete in Shenzhen instead.
Marcel Granollers and Marcin Matkowski were the defending champions, but Granollers chose to compete in Beijing instead. Matkowski played alongside Aisam-ul-Haq Qureshi, but lost in the first round to Santiago González and Julio Peralta.
John Isner and Jack Sock were the defending champions but withdrew from their first round match.
Łukasz Kubot and Marcelo Melo were the defending champions, but they were defeated in the second round by Jonathan Erlich and Marcin Matkowski.
Julien Benneteau and Nicolas Mahut were the defending champions, but lost in the semifinals to Raven Klaasen and Michael Venus.
Raven Klaasen and Rajeev Ram were the defending champions, but chose not to participate together. Klaasen played alongside Michael Venus, but lost in the second round to Ivan Dodig and Ram. Dodig and Ram lost in the quarterfinals to John Isner and Jack Sock.
Pierre-Hugues Herbert and Nicolas Mahut won the men's doubles tennis title at the 2018 French Open, defeating Oliver Marach and Mate Pavić in the final, 6–2, 7–6(7–4). Herbert and Mahut were the third all-French team to reach the French Open men's doubles final in six years.
Ben McLachlan and Yasutaka Uchiyama were the defending champions but chose not to participate together. McLachlan played alongside Jan-Lennard Struff and successfully defended the title, defeating Raven Klaasen and Michael Venus in the final, 6–4, 7–5. Uchiyama teamed up with Joe Salisbury, but lost in the semifinals to Klaasen and Venus.
Oliver Marach and Mate Pavić were the defending champions, but lost to Ben McLachlan and Jan-Lennard Struff in the semifinals.
Raven Klaasen and Michael Venus were the defending champions, but lost in the first round to Jonathan Eysseric and Gilles Simon.
Juan Sebastián Cabal and Robert Farah were the defending champions and successfully defended their title, defeating Raven Klaasen and Michael Venus in the final, 6–1, 6–3.
Łukasz Kubot and Marcelo Melo were the two-time defending champions, but lost in the final to Raven Klaasen and Michael Venus, 6–4, 3–6, [4–10].
Jamie Murray and Bruno Soares were the defending champions, but chose not to participate together. Murray played alongside his brother Andy but lost in the quarterfinals to Raven Klaasen and Michael Venus. Soares teamed up with Mate Pavić but lost in the first round to Jean-Julien Rojer and Horia Tecău.
Rajeev Ram and Joe Salisbury were the defending champions, but lost in the quarterfinals to John Peers and Michael Venus.
Kevin Krawietz and Horia Tecău defeated Félix Auger-Aliassime and Hubert Hurkacz in the final, 7–6(7–4), 6–4, to win the doubles tennis title at the 2021 Halle Open. It was their first title as a team.
Raven Klaasen and Michael Venus were the reigning champions from when the tournament was last held in 2019, but both players chose to participate with different partners.