| Doubles | |
|---|---|
| 2018 Slovak Open | |
| Champions |  Denys Molchanov  Igor Zelenay |
| Runners-up |  Ramkumar Ramanathan  Andrei Vasilevski |
| Final score | 6–2, 3–6, [11–9] |
Ken and Neal Skupski were the defending champions but only Ken Skupski chose to defend his title, partnering Jonny O'Mara. Ken Skupski lost in the semifinals to Denys Molchanov and Igor Zelenay.
Molchanov and Zelenay won the title after defeating Ramkumar Ramanathan and Andrei Vasilevski 6–2, 3–6, [11–9] in the final.
Jonny O'Mara / Ken Skupski (Semifinals)
Marcin Matkowski / 
Philipp Oswald (First round) Denys Molchanov / Igor Zelenay (Champions)
Gerard Granollers / David Marrero (Semifinals)| First Round | Quarterfinals | Semifinals | Final | ||||||||||||||||||||||||
| 1 | J O'Mara K Skupski | 6 | 6 | ||||||||||||||||||||||||
| G García López S Gutiérrez Ferrol | 4 | 3 | 1 | J O'Mara K Skupski | 4 | 6 | [10] | ||||||||||||||||||||
 M-A Hüsler  S Robert | 4 | 4 | P Raja  A Šančić | 6 | 4 | [6] | |||||||||||||||||||||
| P Raja A Šančić | 6 | 6 | 1 | J O'Mara K Skupski | 4 | 5 | |||||||||||||||||||||
| 3 | D Molchanov I Zelenay | 77 | 6 | 3 | D Molchanov I Zelenay | 6 | 7 | ||||||||||||||||||||
| WC | F Horanský A Molčan | 65 | 4 | 3 | D Molchanov I Zelenay | 6 | 63 | [10] | |||||||||||||||||||
| WC | N Gombos L Klein | 79 | 66 | [13] | WC | N Gombos L Klein | 2 | 77 | [6] | ||||||||||||||||||
 T Brkić A Pavić | 67 | 78 | [11] | 3 | D Molchanov I Zelenay | 6 | 3 | [11] | |||||||||||||||||||
 E Donskoy S Stakhovsky | 6 | 4 | [10] | R Ramanathan A Vasilevski | 2 | 6 | [9] | ||||||||||||||||||||
 D Pel  A Vavassori | 3 | 6 | [4] | E Donskoy S Stakhovsky | 3 | 2 | |||||||||||||||||||||
D Bracciali  A Mies | 63 | 1 | 4 | G Granollers D Marrero | 6 | 6 | |||||||||||||||||||||
| 4 | G Granollers D Marrero | 77 | 6 | 4 | G Granollers D Marrero | 5 | 6 | [6] | |||||||||||||||||||
| WC | A Martin F Polášek | 4 | 6 | [10] | R Ramanathan A Vasilevski | 7 | 4 | [10] | |||||||||||||||||||
| A Bury T-S Weissborn | 6 | 3 | [5] | WC | A Martin F Polášek | 6 | 3 | [8] | |||||||||||||||||||
| R Ramanathan A Vasilevski | 6 | 3 | [10] | R Ramanathan A Vasilevski | 4 | 6 | [10] | ||||||||||||||||||||
| 2 | M Matkowski P Oswald | 3 | 6 | [6] | |||||||||||||||||||||||
Robin Haase and Ken Skupski were the defending champions, but Haase decided not to participate.
Skupski played alongside Jamie Delgado but were eliminated in the semifinals.
Nicolas Mahut and Édouard Roger-Vasselin defeated Dustin Brown and Jo-Wilfried Tsonga 3–6, 6–3, [10–6] in the final to win the title.
Ken Skupski and Neal Skupski were the defending champions, but lost in the semifinals to Tomasz Bednarek and Igor Zelenay.
Ilija Bozoljac and Igor Zelenay were the defending champions but only Zelenay chose to defend his title, partnering Denys Molchanov. Zelenay lost in the quarterfinals to Ken and Neal Skupski.
Pierre-Hugues Herbert and Albano Olivetti were the defending champions but only Olivetti chose to defend his title, partnering Kevin Krawietz. Olivetti lost in the first round to Roman Jebavý and Igor Zelenay.
Fabrício Neis and Caio Zampieri were the defending champions but chose to defend their title with different partners. Neis partnered Guillermo Durán but lost in the semifinals to Ken and Neal Skupski. Zampieri partnered Sergio Galdós but lost in the first round to Julian Ocleppo and Andrea Pellegrino.
Mikhail Elgin and Igor Zelenay were the defending champions but chose not to defend their title.
Gong Maoxin and Zhang Ze were the defending champions but lost in the semifinals to Aliaksandr Bury and Peng Hsien-yin.
Sanchai and Sonchat Ratiwatana were the defending champions but chose not to defend their title.
Julian Knowle and Igor Zelenay were the defending champions but only Zelenay chose to defend his title, partnering Denys Molchanov. Zelenay lost in the semifinals to Ariel Behar and Máximo González.
Roman Jebavý and Antonio Šančić were the defending champions but only Jebavý chose to defend his title, partnering Florin Mergea. Jebavý lost in the first round to Denys Molchanov and Igor Zelenay.
Roman Jebavý and Zdeněk Kolář were the defending champions but only Kolář chose to defend his title, partnering Aldin Šetkić. Kolář lost in the first round to Nikola Čačić and Luca Margaroli.
Guillermo Durán and Andrés Molteni were the defending champions but chose not to defend his title.
Rohan Bopanna and Pablo Cuevas were the defending champions, but Bopanna chose to compete in Basel and Cuevas chose to compete in Lima instead.
Max Mirnyi and Philipp Oswald were the defending champions, but Mirnyi retired from professional tennis at the end of 2018 and Oswald chose to compete in Marrakesh instead.
Julian Ocleppo and Andrea Vavassori were the defending champions but lost in the first round to Jonathan Eysseric and Andrei Vasilevski.
Nick Kyrgios and Jack Sock were the defending champions, but chose not to participate this year.
Denys Molchanov and Igor Zelenay were the defending champions but lost in the semifinals to Jiří Lehečka and Jiří Veselý.
Robin Haase and Matwé Middelkoop were the defending champions, but Middelkoop chose to compete in Båstad instead.
Luke Bambridge and Jonny O'Mara were the defending champions but only O'Mara chose to defend his title, partnering Ken Skupski. O'Mara lost in the semifinals to Hans Podlipnik Castillo and Tristan-Samuel Weissborn.
Luke Bambridge and Jonny O'Mara were the defending champions but chose to defend their title with different partners. Bambridge played alongside Ben McLachlan, but lost in the first round to Wesley Koolhof and Fabrice Martin. O'Mara teamed up with Ken Skupski, but lost in the first round to Mate Pavić and Bruno Soares.