Mobile Suit Crossbone Gundam (機動戦士クロスボーン・ガンダム, Kidō Senshi Kurosubōn Gandamu) is a six-volume manga series written and illustrated by Yuuichi Hasegawa based on notes and information by Yoshiyuki Tomino, serialized in Kadokawa Shoten's Shōnen Ace magazine from December 1994 to March 1997 issues. A sequel to the animated theatrical film Mobile Suit Gundam F91, Crossbone has been officially distributed only in Japan and Italy. Numerous sequels written and illustrated by Hasegawa without Tomino's involvement have been published in Gundam Ace.

In Universal Century (UC) 0133, ten years after the events of F91, Crossbone Vanguard forces attack a transport ship called the Smashion as it heads to the space colonies run by the Jupiter Empire. Tobia Arronax, a 13-year-old boy aboard the ship, flies out in a Batara mobile suit to fight the Crossbone Vanguard, who have long been derided as space pirates. Unfortunately, he is captured by Crossbone Vanguard ace pilot Seabook Arno, who now goes by the name Kincade Nau and brought before their leader, Berah Ronah, who offers him to join the Vanguard or go to Jupiter and forget the attack.

Tobia decides to be with the Vanguard, who reveal to him that the Jupiter Empire has spent several years building up its military strength to destroy the Earth Federation, with whom it has a partnership. Now armed with this information, Tobia is trained in mobile suit piloting by Kincaid and to discover his own Newtype abilities. He flies into action as pilot of the XM-X3 Crossbone Gundam X-3 mobile suit.

Crossbone Gundam has seven sequels, all written and illustrated by Yuichi Hasegawa without Tomino's involvement and published in Gundam Ace:

The characters and mecha of Crossbone Gundam often appear in the SD Gundam G Generation video game series. The series also appears in 2nd Super Robot Wars Alpha, part of the long-running Super Robot Wars franchise; it is the first non-animated series to be given plot significance in a Super Robot Wars game. In 2010, Crossbone Gundam appeared in Another Century's Episode: R, Super Robot Wars' action counterpart.

The animated series Gundam Build Fighters has one of the participants in the Gunpla Battle Championships, Mao Yasaka, fielding a version of the Crossbones called the XM-X9999 Crossbone Gundam Maoh. The sequel series, Gundam Build Fighters Try, features another variant, the XM-X1 Crossbone Gundam Full Cloth, used by Lucas Nemesis.

In a 2016 poll by AnimeAnime.jp, Crossbone Gundam was voted as the most-wanted anime adaptation over any other unadapted manga.