| Date: | 1–7 October |
| Edition: | 3rd (men) 4th (women) |
| Category: | ITF Women's Circuit |
| Location: | Stockton, United States |
| Prize Money: | $100,000 (men) $60,000 (women) |
| Champms: | Lloyd Harris |
| Champmd: | Darian King /  Noah Rubin |
| Champws: | Madison Brengle |
| Champwd: | Hayley Carter / Ena Shibahara |
The 2018 Stockton Challenger was a professional tennis tournament played on outdoor hard courts. It was the third and fourth editions of the tournament and was part of the 2018 ATP Challenger Tour and the 2018 ITF Women's Circuit. It took place in Stockton, United States, on 1–7 October 2018.
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
 Australia | Jordan Thompson | 106 | 1 | |
| United States | Reilly Opelka | 125 | 2 | |
| Henri Laaksonen | 128 | 3 | ||
| Lloyd Harris | 129 | 4 | ||
 Norway | Casper Ruud | 136 | 5 | |
| United States | Noah Rubin | 138 | 6 | |
| Australia | Alex Bolt | 162 | 7 | |
| Australia | Marc Polmans | 165 | 8 |
The following players received wildcards into the singles main draw:
Jenson Brooksby Tom Fawcett Thai-Son KwiatkowskiThe 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:
| Country | Player | Rank1 | Seed | |
|---|---|---|---|---|
| United States | Madison Brengle | 95 | 1 | |
| United States | Jessica Pegula | 136 | 2 | |
 Russian Federation | Sofya Zhuk | 137 | 3 | |
 Czech Republic | Marie Bouzková | 147 | 4 | |
| United States | Kristie Ahn | 149 | 5 | |
| United States | Jamie Loeb | 177 | 6 | |
 Brazil | Beatriz Haddad Maia | 196 | 7 | |
| United States | Lauren Davis | 249 | 8 |
The following players received a wildcard into the singles main draw:
Hayley Carter Victoria Duval Jamie Loeb Danielle WillsonThe following players received entry into the singles main draw using a junior exempt:
The following players received entry from the qualifying draw:
The following player received entry as a lucky loser:
See main article: 2018 Stockton Challenger – Men's singles.
Marc Polmans 6–2, 6–2.See main article: 2018 Stockton Challenger – Women's singles.
Madison Brengle def. Danielle Lao, 7–5, 7–6(12–10)See main article: 2018 Stockton Challenger – Men's doubles.
Noah Rubin def. 
Sanchai Ratiwatana / Christopher Rungkat 6–3, 6–4.See main article: 2018 Stockton Challenger – Women's doubles.
Hayley Carter / Ena Shibahara def. Quinn Gleason / Luisa Stefani, 7–5, 5–7, [10–7]