| Henry O'Brien | |
| Earl of Thomond | |
| Tenure: | 1624–1639 |
| Predecessor: | Donogh, 4th Earl |
| Successor: | Barnabas, 6th Earl |
| Spouse: | Mary Brereton |
| Issue: | Margaret, & others |
| Issue-Link: |
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| Father: | Donogh, 4th Earl |
| Mother: | Elizabeth FitzGerald |
| Death Date: | 26 July 1639 |
| Burial Place: | St Mary's Cathedral, Limerick |
Henry O'Brien, 5th Earl of Thomond PC (Ire) (1588–1639), styled Lord Ibrickane until 1624, was summoned to the House of Lords of the Irish Parliament of 1613–1615.
Henry was born the eldest son of Donogh O'Brien and Elizabeth FitzGerald. His father was the 4th Earl of Thomond. His father's family were the O'Briens, an important Gaelic Irish dynasty, that descended from Brian Boru, medieval high king of Ireland.
Henry's mother was the fourth daughter of Gerald FitzGerald, 11th Earl of Kildare and his wife Mabel Brown.
On 13 July 1608 O'Brien married Mary Brereton, a rich heiress, the only daughter of William Brereton, 1st Baron Brereton and Margaret Savage.
Henry and Mary had five daughters:
O'Brien was summoned on 3 March 1613 as Lord Ibrickane to the Irish House of Lords of the Irish Parliament of 1613–1615, the only parliament of King James I in Ireland.
Ibrickane succeeded his father on 5 September 1624 as the 5th Earl of Thomond.
Thomond died in 1639 and was buried in St Mary's Cathedral, Limerick. He had no son and was succeeded in his titles by his brother Barnabas O'Brien, 6th Earl of Thomond.