| Doubles | |
|---|---|
| 2018 Banja Luka Challenger | |
| Champions | |
| Runners-up | |
| Score | 7–5, 4–6, [10–7] |
Marin and Tomislav Draganja were the defending champions, but only Tomislav chose to defend his title, partnering Alessandro Giannessi. Tomislav Draganja lost in the quarterfinals to Andrej Martin and Hans Podlipnik Castillo.
Martin and Podlipnik Castillo won the title after defeating Laurynas Grigelis and Alessandro Motti 7–5, 4–6, [10–7] in the final.
Kevin Krawietz / Andreas Mies (quarterfinals)
Ante Pavić / Antonio Šančić (first round)
Julian Ocleppo / Andrea Vavassori (first round)
Nikola Ćaćić / 
Tristan-Samuel Weissborn (quarterfinals)| First round | Quarterfinals | Semifinals | Final | ||||||||||||||||||||||||
| 1 | 77 | 6 | |||||||||||||||||||||||||
| 61 | 4 | 1 | 0 | 0 | |||||||||||||||||||||||
| WC |  Stefan Granolić Miloš Milaković | 2 | 0 | 6 | 6 | ||||||||||||||||||||||
| 6 | 6 | 1 | 3 | ||||||||||||||||||||||||
| 3 | 4 | 3 | 6 | 6 | |||||||||||||||||||||||
| 6 | 6 | 6 | 4 | [10] | |||||||||||||||||||||||
| 4 | 64 | 2 | 6 | [8] | |||||||||||||||||||||||
| 6 | 77 | 7 | 4 | [10] | |||||||||||||||||||||||
| 6 | 6 | 5 | 6 | [7] | |||||||||||||||||||||||
| WC | Ivan Bjelica Darko Jandrić | 3 | 4 | 6 | 79 | ||||||||||||||||||||||
| 3 | 1 | 4 | 4 | 67 | |||||||||||||||||||||||
| 4 | 6 | 6 | 65 | 65 | |||||||||||||||||||||||
| WC | Vanja Dobrnjac Ivan Randjelović | 2 | 2 | 77 | 77 | ||||||||||||||||||||||
| 6 | 6 | 6 | 7 | ||||||||||||||||||||||||
| Alt | 7 | 1 | [10] | Alt | 0 | 5 | |||||||||||||||||||||
| 2 | 5 | 6 | [2] | ||||||||||||||||||||||||
Alessandro Giannessi and Gianluca Naso were the defending champions. Giannessi did not compete, while Naso partnered Alessio di Mauro, and lost in the first round to Gerard Granollers and Jordi Samper Montaña.
Matteo Donati and Stefano Napolitano were the defending champions, but Donati did not participate. Napolitano partnered with Lorenzo Sonego, but they lost to Andrea Arnaboldi and Hans Podlipnik-Castillo in the quarterfinals.
Guido Andreozzi and Facundo Argüello are the defending champions, but chose not to participate. Gero Kretschmer and Alexander Satschko won the title, defeating Kenny de Schepper and Maxime Teixeira 7–6(7–3), 6–4.
Víctor Estrella Burgos was the defending champion and successfully defended his title, defeating Thomaz Bellucci in the final, 4–6, 7–6(7–5), 6–2.
Tomasz Bednarek and Mateusz Kowalczyk were the defending champions but chose not to defend their title.
Johan Brunström and Andreas Siljeström were the defending champions but lost in the quarterfinals to Marin and Tomislav Draganja.
Marcelo Demoliner and Fabrício Neis were the defending champions but chose not to defend their title.
Martin Kližan and David Marrero were the defending champions, but Kližan chose not to participate this year and Marrero chose to compete in Båstad instead.
Kevin Krawietz and Albano Olivetti were the defending champions but lost in the first round to Aliaksandr Bury and Andreas Siljeström.
James Cerretani and Philipp Oswald were the defending champions, but Cerretani chose to compete in Sofia instead. Oswald played alongside Treat Huey, but lost in the first round to Alessandro Motti and Stefano Travaglia.
Julian Knowle and Adil Shamasdin were the defending champions but chose not to defend their title.
Marin and Tomislav Draganja were the defending champions but chose not to defend their title.
Tomislav Brkić and Ante Pavić were the defending champions but chose not to defend their title.
Zdeněk Kolář and Lukáš Rosol were the defending champions but chose not to defend their title.
Julian Ocleppo and Andrea Vavassori were the defending champions but chose to defend their title with different partners. Ocleppo partnered Andrea Pellegrino but lost in the first round to David Marrero and Roberto Maytín. Vavassori partnered Andrei Vasilevski but lost in the final to Tomislav Brkić and Ante Pavić.
Daniele Bracciali and Matteo Donati were the defending champions but chose not to defend their title.
Filippo Baldi and Andrea Pellegrino were the defending champions but chose not to defend their title.
Andre Begemann and Dustin Brown were the defending champions but only Begemann chose to defend his title, partnering Florin Mergea.
Karol Drzewiecki and Filip Polášek were the defending champions but only Drzewiecki chose to defend his title, partnering Maciej Smoła. Drzewiecki lost in the first round to Matwé Middelkoop and Hans Podlipnik Castillo.
Andrej Martin and Hans Podlipnik Castillo were the defending champions but chose not to defend their title.
