梅林（英语：Merlin），或译魔灵、密林、默林、墨林或穆林，是英格兰及威尔斯神话中的传奇魔法师，他法力强大同时充满睿智、能预知未来和变形，并因为扶助亚瑟王登位而闻名并留下种种事迹。对于这角色原型的描述初见于中世纪作家谢菲（Geoffrey of Monmouth）的著作《不列颠诸王史》（Historia Regum Britanniae）一书，谢菲很可能融合了多个人物的特质，经过撮合创作后便诞生出梅林（英文：Merlin Ambrosius，凯尔特文：Myrddin Emrys）了。

谢菲的著作译本甫推出便大受欢迎（在威尔斯地区尤甚），令他不久之后开始着手为梅林塑造更为全面的巫师形象：由梦魇与凡间女子结合所生，该血统使梅林继承了超自然的力量和技能；另外，通过连串的策划和计谋，梅林热心地导演了亚瑟王的出生并努力使其成为明君，直到他自己被湖中妖女（Lady of the Lake）蛊惑和监禁。

Merlin is a legendary figure best known as the wizard featured in Arthurian legend. The standard depiction of the character first appears in Geoffrey of Monmouth's Historia Regum Britanniae, written c. 1136, and is based on an amalgamation of previous historical and legendary figures. Geoffrey combined existing stories of Myrddin Wyllt (Merlinus Caledonensis), a North Brythonic prophet and madman with no connection to King Arthur, with tales of the Romano-British war leader Ambrosius Aurelianus to form the composite figure he called Merlin Ambrosius (Welsh:Myrddin Emrys). He is allegedly buried in the Broceliande forest, near Paimpont in Brittany.