Barry John Yelverton, 3rd Viscount Avonmore (21 February 1790 – 24 October 1870) was an Irish nobleman.

He was the son of William Charles Yelverton, 2nd Viscount Avonmore and Mary Reade, eldest daughter of John Reade. In 1814, he succeeded his father as viscount.

He married, firstly, Jane Boothe, daughter of Thomas Boothe, in 1811 and had the following issue:

• Hon. Barry Charles Yelverton (1814-1853)
• Hon. Sydney Eloisa Yelverton (1817-1883)
• Hon. George Frederick William Yelverton (1818-1860)
• Hon. Mary Augusta Yelverton (1820-1843)
• Hon. Adelaide Matilda Yelverton (1821-1884), married 1860, Lt-Gen Humphrey Lyons
  Humphrey Lyons
  Humphrey Lyons was born Hampshire, England in 1802, the ninth of twelve sons of John Lyons of Antigua and St Austin's, Hants, and Catherine , daughter of Maine Swete Walrond, 5th Marquis de Vallado....
  
  , Indian Army

His first wife having died in 1821, Yelverton married secondly, Cecilia O'Keefe, daughter of Charles O'Keefe and Letitia Yelverton, on 1 August 1822. They had the following issue:

• Hon. Letitia Yelverton (1823-)
• Hon. William Charles Yelverton, 4th Viscount Avonmore (1824-1883)
• Hon. Louisa Elizabeth Yelverton (1827-)
• Hon. Cecilia Priscilla Yelverton (1829-1854)
• Hon. Walter Algionby Yelverton (1832-1844)
• Hon. Anna Yelverton (1833-)
• Hon. Maletta Yelverton (1839-)

Yelverton died in Dublin and was succeeded in the viscountcy by his third and oldest surviving son William

William Yelverton, 4th Viscount Avonmore

Major William Charles Yelverton, 4th Viscount Avonmore was an Irish nobleman and soldier. He was the son of Barry John Yelverton, 3rd Viscount Avonmore and Cecilia O'Keeffe. Major William Charles Yelverton gained the rank of Major in the service of the Royal Artillery...