The Aran Islands (Irish: Oileáin Árann — Aran Islands pronunciation: [ˈɪlɑːn ˈɑːrənʲ]) or The Arans (na hÁrainneacha — [nə ˈhɑːrənʲəxə]) are a group of three islands located at the mouth of Galway Bay, on the west coast of Ireland. They constitute the barony of Aran in County Galway, Ireland. From west to east they are: Inishmore (Árainn Mhór/Inis Mór — [ˈɑːrənʲ woːr] or [ˈɪnɪɕ woːr ˈɑːrənʲ]), the largest; Inishmaan (Inis Meáin/Inis Meadhóin — [ˈɪnɪɕ mʲɑːn]), the second-largest; and Inisheer (Inis Thiar/Inis Oírr/Inis Oirthir — [ˈɪnɪɕ iːr] or [ˈɪnɪɕ siːr]), the smallest. Irish is the main spoken language on all three islands, and is the language used naming the islands and their villages and townlands.

The approaches to the bay between the Aran Islands and the mainland are as follows:

The islands' geology is mainly karst limestone and is thus closely related to The Burren in Co. Clare (to the east), not the granites of Connemara to the north. This is most obvious in the construction of the walls around the fields.