| 2012 Keio Challenger | |
|---|---|
| Date | 12–18 November |
| Edition | 8th |
| Surface | Hard |
| Location | Yokohama, Japan |
| Champions | |
| Singles | |
 Matteo Viola | |
| Doubles | |
 Prakash Amritraj /  Philipp Oswald | |
The 2012 Keio Challenger was a professional tennis tournament played on hard courts. It was the eighth edition of the tournament which was part of the 2012 ATP Challenger Tour. It took place in Yokohama, Japan between 12 and 18 November 2012.
| Country | Player | Rank1 | Seed |
|---|---|---|---|
 JPN | Tatsuma Ito | 65 | 1 |
 USA | Rajeev Ram | 112 | 2 |
| JPN | Yūichi Sugita | 121 | 3 |
| ITA | Matteo Viola | 149 | 4 |
| JPN | Hiroki Moriya | 186 | 5 |
 TPE | Chen Ti | 202 | 6 |
 GBR | Jamie Baker | 237 | 7 |
 AUS | Brydan Klein | 244 | 8 |
The following players received wildcards into the singles main draw:
Toshihide Matsui Yoshihito Nishioka Masato Shiga Kaichi Uchida The following players received entry from the qualifying draw:
Yuichi Ito Yuuya Kibi Shuichi Sekiguchi
Michael Venus Matteo Viola def. 
Mirza Bašić, 7–6(7–3), 6–3 Prakash Amritraj / Philipp Oswald def. 
Sanchai Ratiwatana / Sonchat Ratiwatana, 6–3, 6–4