This is a list of all the minor characters in the Haikyū!! universe. The characters are listed under the schools or organizations they're affiliated with.
- Karasuno High's Vice Principal (Voice Actor: Yasumichi Kushida): He first appears in Chapter 2 and Season 1, Episode 2. He's the vice principal of Karasuno High, who's known for his wig to cover up a balding head. He causes a lot of trouble for the Boys' Volleyball Team and it has gotten worse since Hinata and Kageyama's fight. In the beginning of the series, Hinata and Kageyama nearly got the club in trouble when they played a mini match against each other and knocked the vice principal's wig off his head; it ultimately landed on Daichi's head, traumatizing the captain for a while.
- Yū Ogasawara (Japanese: 小笠原 優 Ogasawara Yū) (Voice Actor: Misuzu Togashi): He first appears in Chapter 83 and Season 2, Episode 6. He is one of Ikkei Ukai's students at his volleyball school. He quickly becomes friends with Hinata when the teenager joins the school. After the Spring High begins, Yū often accompanies his teacher and several other students to Karasuno's games and cheers on Hinata while chatting with Yachi.
- Hiroki Ogasawara (Japanese: 小笠原 大樹 Ogasawara Hiroki): He first appears in Chapter 84 and Season 2, Episode 6. He is the middle schooler older brother of Yū and one of Ikkei Ukai's students as Setter.
- Taku Sugano, Rintarou Hoshi and Riku Ogata are the other grade schoolers that, like Yū, are Ikkei's students. They all first appear in Chapter 83 and Season 2, Episode 6.
- Mao Aihara (Voice Actor: Rie Suegara): She first appears in Season 1, Episode 14. She is a member of the Karasuno Girls' Volleyball Club and wears the number two jersey in the Interhigh Preliminary match. After the match and hearing her teammate's comment about Michimiya, she reveals that she (Michimiya) is trying to stay composed because of the fact that she is their captain and that she is waiting for the chance to be out of sight to let her emotions overcome her. She was also with Michimiya and Sasaki when they greet the boys back after their victory against Seijō in the Spring High Preliminary.
- Chizuru Sasaki (Japanese: 佐々木千鶴 Sasaki Chizuru) (Voice Actor: Hyang Ri Kim): She first appears in Season 1, Episode 16. She is a member of the Karasuno Girls' Volleyball Club and wears the number eleven jersey in the Interhigh Preliminary match. She is a second-year. During the match, due to her poor receiving skills, the opponents often aimed their serves at her and stole a lot of points from her team. As a result, she blamed herself for their loss but was comforted by Michimiya.
- Shizuyasu Yokoyama (Japanese: 横山静康 Yokoyama Shizuyasu) (Voice Actor: Hiroshi Iwasaki): He first appeared in Chapter 149 and Season 3, Episode 1. He appears to be a long time and avid fan of Karasuno's Boys' Volleyball team. It is said that he will cheer for the plays he think are good, and boo the bad ones. The current Karasuno third years remember him coming to watch their games during their first year and calling the team fallen crows. Yokoyama is seen cheering for Karasuno ever since the Shiratorizawa match.
- Asuka Hirama (Voice Actor: Haruka Terui): She first appears in Season 1, Episode 20. She is one of the girls who had come to cheer Aobajōsai, especially Oikawa, during the Interhigh Preliminary. She wonders why Karasuno couldn't get the serve even though it wasn't Oikawa's, and Takinoue explains to her the reason. She thanks him later after adding that the players are thinking about a lot of things whilst they are on the court. Although attending the volleyball match initially to support Seijō, at the end of the match they are seen clapping for Karasuno when they bow to their supporters.
- Manaka Ujiie (Voice Actor: Ai Kakuma): She first appears in Season 1, Episode 20. She is one of the girls who had come to cheer Aobajōsai, especially Oikawa, during the InterHigh Preliminary. Just like Hirama, she attended the volleyball match to cheer Aobajōsai on but can be seen at the end of the match clapping alongside her friends when Karasuno bows to their spectators.
- Kiyoshi-san (Voice Actor: Eiji Takemoto): He first appears in Season 2, Episode 23. Not much is known about this man, other than that he attended the Aobajōsai vs. Karasuno match at the Spring High Preliminary to support Kyōtani. He was fundamental to the development of Kyōtani's character, as he was the one who had influenced the boy to cooperate with his teammates and face each other head-on if he wanted to perform at his best. Kiyoshi's words prove to be useful as when Kyōtani placed his trust on his team, they were able to spike successfully past their opponents.
- Takeru Oikawa (Voice Actor: Yuka Maruyama): He first appears in Season 2, Episode 6. He is Oikawa's nephew who attends volleyball classes at Lil'Tykes Volleyball.
- Jin Soekawa (Japanese: 添川 仁 Soekawa Jin): He is Shiratorizawa's vice-captain and holds the number two.
- Yunohama: He is one of Shiratorizawa's pinch servers and holds the number 7. He is a second-year and played in the match against Karasuno during the Spring High. He was later present during Ushijima's speech to his underclassmen before retiring. His main weapon is the jump float serve,
- Seiji Okudake (Voice Actor: Kouhei Fukuhara): He first appears in Season 2, Episode 15 . He is the former captain of Johzenji who retired after Interhigh. He is a third-year.
- Mika Yamaka (Japanese: 山架美華 Yamaka Mika): She first appears in Chapter 206. Birthday: Dec. 19, 3rd year Class 4, Height: 156.3 cm (5' 1.5"), Weight: 44.3 kg, Favorite Food: Pretz (roast), Current Concern: She doesn't know what Instagram is anymore. Mika is Daishō's ex-girlfriend who broke up with him sometime before the Tokyo Spring High Representative Playoffs, most likely because of his sole focus on volleyball. Unbeknownst to him, she'd attended his match against Nekoma and after seeing his determination, began to understand his interests better. She later approached him after his loss and comforted him, asking him to teach her volleyball sometime; they most likely have reconciled after this.
- Genta Okuda (Japanese: 奥田 元太 Okuda Genta): He first appears in Chapter 151. Currently 2nd year of high school, used to play volleyball in middle school, Height: 174.2 cm, Weight: 63.3 kg. Okuda is always seen with Takanashi together watching the matches at the Spring Interhigh. He used to be a volleyball player in middle school, so he is well aware of the basics.
- Hiromi Takanashi (Japanese: 高梨 ひろみ Takanashi Hiromi): She first appears in Chapter 151. Currently 2nd year of high school, used to play volleyball in middle school, Height: 159.5 cm, Weight: 47.5 kg. Takanashi is always seen together with Okuda watching the matches at the Spring Interhigh. She is revealed to be a fan of the Miya brothers, but says she is starting to become a Karasuno fan after watching their match. She also wonders if she should take up volleyball again.