祖先崇拜，或称祭祀祖先、祖灵信仰、敬祖、祭拜祖先、拜公妈，是指一种，祭祀、供奉祖先，类似宗教仪式与习惯的行为。基于死去的祖先仍然深深存在后人心中，仍然会影响到现世，并且对子孙的生存有影响的信仰。俚语俗话说「吃菓子拜树头、饮泉水思源头」。

在大部分不同文化中，祖先崇拜和神灵崇拜不太一样，对神崇拜大多是希望祈求一些利益，但人们对祖先的信仰，并不仅仅是希望祈求一些好处，也是表达亲情或者对先人的尊敬。儒教文化将祖先当作神灵一样崇拜。受此影响，一般中国人除了敬祖外，还希望受到祖先神灵的庇佑，“祖先保佑”一样是最常见的祈福语。

The veneration of the dead, including one's ancestors, is based on love and respect for the deceased. In some cultures, it is related to beliefs that the dead have a continued existence, and may possess the ability to influence the fortune of the living. Some groups venerate their direct, familial ancestors; some faith communities, in particular the Catholic Church, venerate saints as intercessors with God, as well as praying for and to departed souls in Purgatory.