* ActingForTwo: In the stage play adaptation, actors often play multiple roles (justified as the restrictions can only allow so many people in a theatre production). Most of them simply switch between their main roles and background characters (for example, Kenma, Kuroo, Bokuto and Akaashi also acting as Ukai Sr's students in two plays), but some do get to play additional significant roles:
** Saeko's actress Momoko Sadachi in the ''Start of the Giant'' stage play also plays the Johzenji manager Hana Misaki. When Tanaka bumps into Hana before the match, [[LeaningOnTheFourthWall he can't help but stare at her in confusion]].
** The stage play [[SignificantDoubleCasting occasionally emphasise character comparisons by making the same actor play them]], such as Ukai Jr and Sr being played by the same actor to hammer down how similar the grandson and grandpa duo are.
* ActorSharedBackground:
** Multiple voice actors of the Inarizaki team are from Kansai and so speak the dialect like their characters.
** Some cast members of the stage play adaptations also played volleyball in high school, with a couple even having competed at Nationals. Hell, some of the captains were actually captains of their own teams back in high school, such as Kentaro Akisawa (2016-2017 Daichi), Keita Tanaka (2015, 2018 Daichi), and Rin Yanagihara (Nakashima).
* CharacterOutlivesActor: Ukai's voice actor Creator/KazunariTanaka died during the production of Season 3, leaving Creator/HisaoEgawa to suddenly take over in Episodes 9 and 10 (he would reprise the role for later seasons). Ukai's famous motivational shout from Episode 8 is said to be the last lines he recorded.
* CreatorCouple: Creator/AdamGibbs, the English voice of Suga is married to Rebekah Stevens, English voice of Kiyoko.
* CrosscastRole: Due to the restrictions of the stage plays, a bunch of the actors who play members of the boys' team also portray female spectators. Some examples include a trio of school girls in 2015's ''A View From The Top'' and ''Karasuno Revival'' being played by Ukai's, Yamaguchi's, and Nishinoya's first actors, and a duo of female spectators in ''Winners and Losers'' being portrayed by Kenma's and Kuroo's actors.
* TheDanza: In the stage plays, Kageyama was portrayed by Tatsuya Kageyama from the 2017 installment ''Summer of Evolution'' to the 2018 installment ''The Strongest Team''.
* DawsonCasting: Many of the actors who play the high-school-aged characters take on the roles in their 20s to ''30s''. Although several actors playing the student characters are under 20 in their first appearance, they eventually outgrow their characters significantly as their duration in the stage plays went on.
* DuelingShows: Aired around the same time as ''Anime/{{Free}}''. Both are sports anime featuring CastFullOfPrettyBoys with a strong passion for their particular sport.
* TheForeignSubtitle: In Italian, the series is named ''Haikyuu!!: L'asso del volley'' (''Haikyuu!!: The Ace of Volleyball'').
* GenreRelaunch: ''Haikyuu!!'', along with ''Anime/{{Free}}'', has helped revive interest in sports anime among the North American fanbase.
* GodNeverSaidThat: An alleged interview in which series creator Haruichi Furudate seemingly confirms [[HoYay Tsukishima and Yamaguchi]] to be [[OfficialCouple an item]] has been thoroughly debunked, but still occasionally manages to fool new fans.
* IronyAsSheIsCast: Creator/AyumuMurase, Hinata's voice actor, was born and grew up in California, where he became fluent in both English and Japanese. However, his character is BookDumb and has great difficulty in English.
* OutdatedByCanon: Many fanfics depict Kageyama [[spoiler:as an only child]] since his difficult personality and the lack of emphasis and information on [[spoiler:his family and home life]] for majority of the series (unlike the other main character Hinata whose [[spoiler:sister occasionally shows up]]) make the theory fairly realistic. [[spoiler:A whopping 387 chapters into the manga without any particular hints, it's revealed that Kageyama ''does'' in fact have a sibling -- a much older sister called Miwa.]]
* OtakuOClock: While the first season aired at 5pm, the other seasons ran at late-night time slots.
* TheOtherDarrin:
** During production of the third season, Creator/KazunariTanaka, Ukai's voice actor, died of a brain stem hemorrhage. Creator/HisaoEgawa filled in as the character from Episode 9 of Season 3 onwards.
** Many of the stage play actors have been replaced in its run (usually due to the original actors going on to bigger projects). The largest change occurred with the Karasuno team (including the managers and coaches), who were recast after the 2018 installment, ''The Strongest Team''.
* RealLifeRelative: Young Atsumu and Osamu Miya are voiced by Satsumi and Risae Matsuda respectively, who are twins in real life.
* ScheduleSlip: Part 2 of Season 4 was meant to air in July 2020 but was then rescheduled to October 2020 due to the COVID-19 lockdown affecting production. The pandemic also similarly caused a delay in one of the Shounen Jump issues during ''Haikyuu!!''s run due to a staff member testing positive.
* SpoiledByTheCastList: Prior to Inarizaki's anime debut, character sheets and voice cast announcements were made for several members on the official website and social media. One of these characters is a major reveal in the manga by both name and character design alone -- [[spoiler:Osamu Miya, aka Atsumu's twin brother]]. The voice actor even appeared in an official ''Haikyuu!!'' livestream event well ahead of their debut in Season 4 Episode 13.
* SpoiledByTheMerchandise: A volleyball magazine did a ''Haikyuu!!'' feature in its July 2020 issue just before the manga finished, specifically on [[spoiler:members of the National Team]]. While this didn't dampen anyone's excitement, this actually spoiled what was meant to be a reveal for the final chapter [[spoiler:aka Japan's lineup for the Olympics]]. Additionally, one of the characters shown is [[spoiler:Morisuke Yaku]]. The problem? The character in question hadn't returned to the manga yet, and their reappearance was also meant to be a surprise for the last chapter.
* StarMakingRole:
** While Creator/AyumuMurase had some decent gigs beforehand, he shot to stardom once he started voicing Hinata and has gotten many other major roles since then.
** Kageyama was not only one of Creator/KaitoIshikawa's first major roles but also his first popular one. He would go on to voice significant characters in many other anime after his breakthrough with ''Haikyuu!!'' in 2014.
* WhatCouldHaveBeen:
** The original pilot chapter of the manga had Kageyama actively trying to convince Hinata to join because of his abnormal ability to jump, only for Hinata to balk every time. They also became very close friends much faster than in the actual storyline.
** The full pilot reveals quite a bit that didn't make it into the canon story:
*** Kageyama was the protagonist instead of Hinata.
*** Hinata was described as being clumsy when it came to sports, being more of an AccidentalAthlete.
*** Kageyama was Number 10 in the chapter but 6 on the cover art, while Hinata was Number 12. This was later changed to Kageyama being Number 9, Hinata 10, Yamaguchi 12, and Ennoshita 6.
*** Daichi, Kageyama, Hinata, and Tanaka were the only members of Karasuno to appear; Sugawara, Asahi, Nishinoya, Ennoshita, Narita, Kinoshita, Tsukishima, and Yamaguchi had not been introduced.
*** Karasuno was initially named "Hiashi."
*** Originally, Tanaka was meant to be more of jerkass who was rude to the leading pair, but particularly to Hinata. The version of him that made it to print was mellowed out into a strong BigBrotherMentor with [[BigBrotherInstinct equally-strong protective instincts]] towards Hinata.

----