| Date: | 5–11 February |
| Edition: | 2nd |
| Surface: | Hard |
| Location: | San Francisco, United States |
| Champs: | Jason Jung |
| Champd: | Marcelo Arévalo /  Roberto Maytín |
The 2018 Kunal Patel San Francisco Open was a professional tennis tournament played on indoor hard courts. It was the second edition of the tournament and was a part of the 2018 ATP Challenger Tour. It took place in San Francisco, United States from February 5–11, 2018.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Kazakhstan | Alexander Bublik | 131 | 1 | |
| Mackenzie McDonald | 158 | 2 | ||
| Michael Mmoh | 164 | 3 | ||
| Denis Kudla | 167 | 4 | ||
| Bradley Klahn | 175 | 5 | ||
| Noah Rubin | 180 | 6 | ||
 Canada | Filip Peliwo | 186 | 7 | |
| Canada | Brayden Schnur | 192 | 8 |
The following players received wildcards into the singles main draw:
Christopher Eubanks
Florian Lakat Danny ThomasThe following players received entry from the qualifying draw:
JC Aragone
Máximo González Jared Hiltzik
Karue SellSee main article: 2018 Kunal Patel San Francisco Open – Singles.
See main article: 2018 Kunal Patel San Francisco Open – Doubles.
Roberto Maytín def. 
Luke Bambridge / Joe Salisbury 6–3, 6–7(5–7), [10–7].