八幡神（日语：はちまんしん、やはたのかみ、やわたのかみ）是日本的战神、八幡宫的祭神，自古以来就是日本皇室的祖神、源氏的氏神，也称为八幡大菩萨。

《续日本纪》中记载圣武天皇在藤原广嗣之乱时，下诏大将军大野东人祈请八幡神之事。从钦明天皇的时代开始，八幡神乃被视为应神天皇。平安时代以来，八幡神受到神佛习合思想的影响，成为佛教的护法神，而有八幡大菩萨的称号（也是日本佛教中阿弥陀如来之权现）。

八幡神是日本天皇祖神，所以源自皇室的源氏武士也以八幡神为氏神；进入镰仓时代，由于源赖朝任幕府将军、创设镰仓幕府，八幡神也演变为武神与武家的守护神。明治时代，在神佛分离的政策下，佛教式的八幡大菩萨神号被禁止；但是仍根深蒂固存在；太平洋战争末期，在陆军、海军的航空基地可见书写着「南无八幡大菩萨」的旗帜，是飞行员（特别是神风特攻队员）的信仰对象。

In Japanese beliefs, Hachiman(八幡神,Hachiman-jin/Yahata no kami) is the syncretic divinity of archery and war, incorporating elements from both Shinto and Buddhism. Although often called the god of war, he is more correctly defined as the tutelary god of warriors. He is also the divine protector of Japan, the Japanese people and the Imperial House, the Minamoto clan ("Genji") and most samurai worshipped him. The name means "God of Eight Banners", referring to the eight heavenly banners that signaled the birth of the divine Emperor Ōjin. His symbolic animal and messenger is the dove.