William O'Brien, 4th Earl of Inchiquin

The Right Honourable
The Earl of Inchiquin
KB PC(I)
The Right Honourable The Earl of Inchiquin KB PC(I)
Personal details
Born	Ireland
Died	Ireland
Spouse	Lady Anne Hamilton
Parents	William O'Brien, 3rd Earl of Inchiquin (father); Mary O'Brien (mother);
Occupation	Politician

William O'Brien, 4th Earl of Inchiquin, KB, PC(I) (1700 – 18 July 1777) was an Irish peer, Chief of Clan O'Brien, and Whig politician who sat in the House of Commons between 1722 and 1754.