Irish mythology refers to a large body of traditional stories involving gods, supernatural beings, legendary heroes, rulers and otherworldly places. Much of the surviving material was preserved in medieval Irish manuscripts, alongside later oral traditions and folklore.

Well-known figures include Lugh, Brigid and other members of the Tuatha Dé Danann. Modern labels such as "god of" a particular subject can sometimes oversimplify figures whose roles vary between stories.

Irish legendary literature is often organised into broad groupings or cycles, including the Mythological Cycle, Ulster Cycle, Fenian Cycle and Cycle of the Kings. These modern groupings are useful for organising the material, though the original tradition is more complex.

Fairies are strongly associated with Irish folklore and otherworld traditions. There are connections between later fairy belief and earlier mythological material, but mythology and folklore should not always be treated as exactly the same tradition.

No. Irish mythology is one regional tradition within the wider range of cultures often described as Celtic. Welsh, Gaulish and other traditions have their own surviving material and should not be treated as one identical mythology.

Many surviving Irish mythological stories are preserved in medieval manuscripts written by Christian scribes, while other traditions continued orally and appear in later folklore. This means the material reflects several historical layers rather than a single untouched ancient source.