Daniel O'Brien, 3rd Viscount Clare

Daniel O'Brien, 3rd Viscount Clare was an Irish nobleman, the son of Connor O'Brien, 2nd Viscount Clare and Honora O'Brien.

Clare was appointed commander of a newly raised regiment of foot, Clare's Regiment of Foot, an Irish regiment in the Dutch States Army, on 8 August 1674. He was replaced within twelve months by Sir John Fenwick. From July 1751 this regiment was known as the 5th Regiment of Foot.

During the War of the Two Kings, Clare served with the Jacobite Irish Army loyal to James II. He was the commander of Clare's Dragoons regiment which he led against William of Orange at the Battle of the Boyne and later exile in France as part of the Flight of the Wild Geese. He married Philadelphia Lennard, sister of the Earl of Sussex, and together they had three children:

• Honora O'Brien
• Daniel O'Brien, 4th Viscount Clare
• Charles O'Brien, 5th Viscount Clare