O'Brien's Tower marks the highest point of the Cliffs of Moher in County Clare, Ireland. It is located a short distance from the villages Doolin and Liscannor.

The tower was built on the cliffs in 1835 by local landlord and MP Cornelius O'Brien as an observation tower for the tourists who frequented the cliffs at the time: "strangers visiting the Magnificent Scenery of this neighbourhood". It is said to have initially served as a teahouse, featuring a large round table with seats of ironwork.

On a clear day the view can extend as far as Loop Head at the southern tip of Clare and beyond to the mountains of Kerry. Looking north, the Twelve Bens in Connemara (also known as the Twelve Pins) beyond Galway Bay can be seen, and typically the Aran Islands to the west.

• Portrait of Ireland: Landscapes, Treasures, Traditions (Dorling Kindersley Travel Guides), 1 August 2000, ISBN 0-7894-6361-X

• Irish Coast Guard Doolin Unit
• The Cliffs of Moher and O'Brien's Tower