Aveline de Clare, Countess of Essex

Aveline de Clare, Countess of Essex (born circa 1178 - died 1225), was a daughter of Roger de Clare, 2nd Earl of Hertford and his wife, Matilda de St. Hilaire. Aveline married twice. Her first husband, William de Munchensy, died in 1204. She was remarried by 29 May 1205, to Geoffrey fitz Peter, Earl of Essex, as his second wife. She was widowed a second time on 14 October 1213.

King John granted the royal right over her remarriage to her step-brother, William, Earl of Arundel, along with the guardianship of her children by William de Montchesney/Munchanesy, on 7 May 1204. Soon after her second marriage she paid the crown for the wardship of John de Wahulle and custody of his land.

In her second widowhood, Countess Aveline made gifts to Holy Trinity, London, for the soul of Geoffrey fitz Peter, part of whose body was buried there. She was buried in Shouldham Priory, founded by Geoffrey fitz Peter in 1198, alongside the rest of her husband's body.