| Date: | 22–28 January |
| Edition: | 12th |
| Surface: | Hard |
| Location: | Rennes, France |
| Champs: |  Vasek Pospisil |
| Champd: |  Sander Gillé / Joran Vliegen |
The 2018 Open de Rennes was a professional tennis tournament played on hard courts. It was the twelfth edition of the tournament and part of the 2018 ATP Challenger Tour. It took place in Rennes, France between 22 and 28 January 2018.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Russian Federation | Mikhail Youzhny | 90 | 1 | |
| Canada | Vasek Pospisil | 105 | 2 | |
| Gastão Elias | 113 | 3 | ||
 Ukraine | Sergiy Stakhovsky | 120 | 4 | |
| Dustin Brown | 129 | 5 | ||
 France | Quentin Halys | 134 | 6 | |
 Lithuania | Ričardas Berankis | 136 | 7 | |
 Slovakia | Norbert Gombos | 137 | 8 |
The following players received wildcards into the singles main draw:
The following player received entry into the singles main draw as a special exempt:
The following player received entry into the singles main draw as an alternate:
The following players received entry from the qualifying draw:
See main article: 2018 Open de Rennes – Singles.
Vasek Pospisil def. Ričardas Berankis 6–1, 6–2.See main article: 2018 Open de Rennes – Doubles.
Sander Gillé / Joran Vliegen def. Sander Arends / Antonio Šančić 6–3, 6–7(1–7), [10–7].
