Angel Beats! is a 13-episode Japanese anime television series produced by P.A. Works and directed by Seiji Kishi. The story was originally conceived by Jun Maeda, who also wrote the screenplay and composed the music with the group Anant-Garde Eyes, with original character design by Na-Ga; both Maeda and Na-Ga are from the visual novel brand Key, who produced such titles as Kanon, Air, and Clannad. The anime aired in Japan between April 3 and June 26, 2010, on CBC. An original video animation (OVA) episode was released in December 2010, and a second OVA was released in June 2015. The story takes place in the afterlife and focuses on Otonashi, a boy who lost his memories of his life after dying. He is enrolled into the afterlife school and meets a girl named Yuri who invites him to join the Afterlife Battlefront, an organization she leads which fights against the student council president Kanade Tachibana, a girl also known as Angel with supernatural powers.

Key worked in collaboration with Dengeki G's Magazine published by ASCII Media Works to produce the project into a media franchise. Four manga series are serialized in Dengeki G's Magazine and Dengeki G's Comic: two illustrated by Haruka Komowata and two drawn by Yuriko Asami. A series of illustrated short stories written by Maeda and illustrated by GotoP were also serialized in Dengeki G's Magazine between the November 2009 and May 2010 issues. Two Internet radio shows were produced to promote Angel Beats!. A visual novel adaptation titled Angel Beats! 1st Beat was produced by Key and released for Windows on June 26, 2015.

Angel Beats! received generally positive reviews from critics. The integration of various individual elements together, such as musical performances, humor and action, was commended in one review but panned in another, saying that the story was overloaded with too many elements. P.A. Works was praised for the animation of the action sequences and attention to detail with the weapons used. A major flaw noted by critics, however, was the length of the anime, with its short run leaving many of the characters' back-stories unexplored. The anime was selected as a recommended work by the awards jury of the 14th Japan Media Arts Festival in 2010.

Angel Beats! is set in the environment of a high school in the afterlife, a type of limbo for people who have experienced trauma or hardships in life and must overcome them before passing on and being reincarnated. The story follows Yuzuru Otonashi, a boy with amnesia who ends up in the afterlife. He meets Yuri Nakamura, a girl who invites him to join the Afterlife Battlefront (死んだ世界戦線, Shinda Sekai Sensen), or SSS, an organization she founded and leads which rebels against an unseen God for their unfair circumstances in life. Their enemy is Angel, the student council president, who has supernatural powers and is believed to be God's associate. After joining the SSS, Otonashi meets other members, including Hideki Hinata, the co-founder; Masami Iwasawa, the lead vocalist of a four-girl rock band, Girls Dead Monster (GDM); and Yui, a younger fan of GDM. Other than the SSS members, the afterlife is populated by fabricated students and teachers, whom Yuri refers to as "non-player characters" (NPCs).

Otonashi participates in several SSS operations and missions, despite still questioning the morality of their actions. During one of GDM's diversion concerts, Iwasawa passes on from the afterlife after achieving satisfaction through her music. After the SSS manages to demote Angel from her position, Otonashi partially regains his memories with the aid of deputy president Ayato Naoi's hypnosis. He later befriends Angel, whose real name is Kanade Tachibana, and remembers the rest of his past while in her presence. Otonashi helps her make peace with the SSS and learns of the afterlife's true purpose. He subsequently offers to aid Kanade in helping other SSS members to pass on, and Kanade is reinstated as student council president in accordance with their plan. They are joined by Hinata and Naoi, with the former helping Yui move on by fulfilling her desire for marriage.

Mysterious shadow-like entities begin appearing, attacking the residents of the afterlife by turning them into NPCs. Otonashi reasons with the other SSS members and many of them agree to pass on in lieu of becoming an NPC. Yuri destroys the source of the shadows, which were created by computers programmed to activate when love was detected in the afterlife to prevent it from becoming a paradise. Her affection for the members of the SSS allow her to finally overcome her regret, and by this time, the only other ones who have not passed on are Otonashi, Kanade, Hinata and Naoi. The five remaining students hold a graduation ceremony before Naoi, Yuri and Hinata pass on leaving only Otonashi and Kanade.

Otonashi confesses to Kanade that he has fallen in love with her and wants them to remain in the afterlife to help others move on. However, Kanade reveals that her regret was being unable to thank her heart's donor, Otonashi, for extending her life. Otonashi is heartbroken after she thanks him and passes on, leaving him alone in the afterlife. Later, two people resembling Otonashi and Kanade encounter each other on the street in the real world. In an alternate epilogue, Otonashi becomes the high school's student council president and helps lost souls depart from the afterlife while waiting to see Kanade again.

The original creators of Angel Beats!, Jun Maeda and Na-Ga of Key, were interviewed in the July 2009 issue of ASCII Media Works' Dengeki G's Magazine. Around the time Key completed the first release of their sixth visual novel Little Busters!, Yōsuke Toba of Aniplex (himself a fan of Key's works) approached Maeda around October 2007 about collaborating to produce an original anime series. Maeda began meeting with Toba and Aniplex on a monthly basis and the story started to gradually progress. Aniplex wanted Maeda to write a screenplay that would be very "Key-like, with touching moments of laughter and tears," but initially Maeda found himself at a loss to write a story more amusing than Little Busters!, because he thought that he had reached a limit with Little Busters! in regards to a "Key-like story". However, one day Maeda was struck by inspiration, where he thought up the initial idea of a story set in the afterlife. Furthermore, with everyone already dead, Maeda conceived of flashy battles where the combatants go all out without fear of death. According to Maeda, the theme of the series is "life", which in Angel Beats! is depicted as a precious and wonderful thing, despite the characters in Angel Beats! who fight against their fate.