| Seiyuu | Role |
| Satsuki Yukino | Saki Kasukabe |
| Nobuyuki Hiyama | Harunobu Madarame |
| Takanori Ooyama | Kanji Sasahara |
| Mitsuki Saiga | Makoto Kousaka |
| Tomokazu Seki | Souichirou Tanaka |
| Kenji Nomura | Mitsunori Kugayama |
| Ayako Kawasumi | Kanako Ohno |
| Kaori Shimizu | Keiko Sasahara (Kanji's Sister) |
| Yuuji Ueda | Genshiken President |
| Kouji Ishii | Haraguchi |
| Sanae Kobayashi | Kitagawa (Episode 5, 7, 8, 11, 12) |
| Akira Ishida | Kuchiki (Episode 7 & OVA) |
| Kaori Mizuhashi | Chika Ogiue (OVA) |
| Hirofumi Nojima | Saki's Ex Boyfried (Episode 4) |
| Kentarou Itou | Sawazaki (Episode 7) |
| Susumu Chiba | Takashi (Episode 10) |
| Youji Ueda | Narration (Episode 6) |