Marquess of Donegall is a title in the Peerage of Ireland, created in 1791 for the Earl of Donegall.

The Marquess holds the subsidiary titles of Earl of Donegall (1647), Earl of Belfast (1791), Viscount Chichester, of Carrickfergus in the County of Antrim (1625), Baron Chichester, of Belfast in the County of Antrim (1625), Baron Fisherwick, of Fisherwick in the County of Stafford (1790), and Baron Templemore, of Templemore in the County of Donegall (1831). All are in the Peerage of Ireland, except the Baronies of Fisherwick and Templemore, which are in the Peerages of Great Britain and the United Kingdom respectively.

Before the passage of the House of Lords Act 1999 the Marquess sat in the House of Lords as Baron Fisherwick and Templemore.

The County in Ireland from which the title is derived is now spelt Donegal.

Viscounts Chichester (1625)

• Edward Chichester, 1st Viscount Chichester (1568-1648)
• Arthur Chichester, 2nd Viscount Chichester (1606-1675) (became Earl of Donegall in 1647)

Earls of Donegall (1647)

• Arthur Chichester, 1st Earl of Donegall (1606-1675)
• Arthur Chichester, 2nd Earl of Donegall (d. 1678)
• Arthur Chichester, 3rd Earl of Donegall (1666-1706)
• Arthur Chichester, 4th Earl of Donegall (1695-1757)
• Arthur Chichester, 5th Earl of Donegall (1739-1799) (became Marquess of Donegall in 1791)

Marquesses of Donegall (1791)

• Arthur Chichester, 1st Marquess of Donegall (1739-1799)
• George Augustus Chichester, 2nd Marquess of Donegall (1769-1844)
• George Hamilton Chichester, 3rd Marquess of Donegall (1797-1883)
• Edward Chichester, 4th Marquess of Donegall (1799-1889)
• George Augustus Hamilton Chichester, 5th Marquess of Donegall (1822-1904)
• Edward Arthur Donald St George Hamilton Chichester, 6th Marquess of Donegall (1903-1975)
• Dermot Richard Claud Chichester, 7th Marquess of Donegall (b. 1916)

Heir Apparent: Patrick Chichester, Earl of Belfast

Lord Belfast's Heir Apparent: James Chichester, Viscount Chichester