The 2018 Sparkassen Open was a professional tennis tournament played on clay courts. It was the 25th edition of the tournament which was part of the 2018 ATP Challenger Tour. It took place in Braunschweig, Germany between 9 and 14 July 2018.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
| Pablo Cuevas | 76 | 1 | ||
 Spain | Roberto Carballés Baena | 79 | 2 | |
| Spain | Jaume Munar | 89 | 3 | |
| Florian Mayer | 91 | 4 | ||
 Moldova, Republic of | ||||
 Estonia | Jürgen Zopp | 107 | 6 | |
| Yannick Hanfmann | 111 | 7 | ||
 Slovakia | Martin Kližan | 115 | 8 | |
| Slovakia | Jozef Kovalík | 117 | 9 |
The following players received wildcards into the singles main draw:
The following players received entry into the singles main draw as alternates:
The following players received entry from the qualifying draw:
Kimmer Coppejans
Maxime Janvier
Jan ŠátralThe following player received entry as a lucky loser:
See main article: 2018 Sparkassen Open – Singles.
Jozef Kovalík 6–2, 3–6, 6–3.See main article: 2018 Sparkassen Open – Doubles.
Santiago González / Wesley Koolhof def. 
Sriram Balaji / Vishnu Vardhan 6–3, 6–3.
