Henry O'Brien
Henry O'Brien may refer to:
- Henry O'Brien, Lord Ibrackan, Irish nobleman and politician
- Henry O'Brien, 5th Earl of Thomond, Irish peer
- Henry O'Brien, 7th Earl of Thomond, Irish peer
- Henry O'Brien, 8th Earl of Thomond, Irish peer and Member of Parliament
- Henry O'Brien (Australian politician), Irish-born New South Wales politician
- Henry O'Brien (classicist), Irish classicist and author
- Henry O'Brien (colonel), colonel of the 11th New York Volunteer Infantry Regiment killed during the New York draft riots
- Henry O'Brien (cyclist), American cyclist
- Henry D. O'Brien, Medal of Honor recipient from the American Civil War
- Henry Joseph O'Brien, American prelate of the Roman Catholic Church
- Henry L. O'Brien, American politician from New York
- Henry X. O'Brien, American lawyer and judge