One Week Friends is a manga series by Matcha Hazuki. It was serialized in Square Enix's Gangan Joker magazine between January 21, 2012 and January 22, 2015. It was first published as a one-shot manga in the magazine's September 2011 issue. The series has since been collected in seven tankōbon volumes. An anime television series adaptation by Brain's Base aired between April 6 and June 22, 2014. Sentai Filmworks licensed the rights to the show in North America and by Madman Entertainment in Australia and New Zealand. A live-action film of the same name was released in February 2017.

Gangan is a manga imprint owned by Square Enix Holdings. It originated as a manga imprint for Enix before the company re-branded as Square Enix. It publishes manga in several anthologies aimed at different reader demographic groups in the Japanese market. Its anthologies are home to some popular Square Enix manga series which were adapted into anime series, like Fullmetal Alchemist, Moribito: Guardian of the Spirit, Nabari no Ou, Inu x Boku SS, The Case Study of Vanitas and Soul Eater. The comics are later collected in paperback volumes under brand names such as Gangan Comics , Gangan Comics Joker and Young Gangan Comics , which identify the anthology of serialisation. These paperback brand names are formed by omitting any gekkan or shōnen in the magazine name and inserting Comics directly after the word Gangan.