Elizabeth de Berkeley, Countess of Warwick

Elizabeth de Berkeley, Countess of Warwick, Baroness de Lisle, and Baroness de Teyes (1386 – 28 December 1422) was an English noblewoman and heiress. She was the only child of Thomas de Berkeley, 5th Baron Berkeley and Margaret de Lisle, 3rd Baroness Lisle.

With her father's death in 1417, Elizabeth and her husband Richard de Beauchamp, 13th Earl of Warwick became involved in an inheritance dispute with her cousin James Berkeley, initiating one of the longest lawsuits in English history.

Elizabeth de Berkeley was the only child born to Thomas de Berkeley, 5th Baron Berkeley by his wife Margaret de Lisle, 3rd Baroness Lisle. As such, Elizabeth was their sole heir, and was to inherit the baronies of Lisle and Tyes from her mother. Margaret died near 1392, but Elizabeth did not succeed to them until the death of Thomas in 1417, as he held the lands by tenure of courtesy. In September 1392, the Baron Berkeley negotiated Elizabeth's marriage to Richard de Beauchamp, eldest son and heir to Thomas de Beauchamp, 12th Earl of Warwick. Elizabeth married him sometime before 5 October 1397, and became the Countess of Warwick in 1403. The marriage remained unconsummated for at least six years. Elizabeth gave birth to three girls:

Elizabeth's level of education and literacy is evident from a 1410 commission asking John Walton to translate Boethius' De consolatione philosophiae; he dedicated it in her name.

An inheritance dispute erupted with her father's death in 1417. Thomas had named her his heir, but many of his lands and estates, including Berkeley Castle, were entailed through the male line to Elizabeth's cousin James Berkeley. Elizabeth and her husband refused to accept the entail, thus "initiat[ing] one of the longest lawsuits in England," which lasted until 1609. After Lord Thomas' death, the Earl and Countess of Warwick quickly took control of the castle and gained the temporary permission of King Henry V to maintain it. James was unable to seize control of the castle, as Warwick and the king were then fighting in France. To gain support in the dispute, Elizabeth sought the help of John, Duke of Bedford while James successfully bribed Humphrey, Duke of Gloucester, each one of the king's brothers. By 1425, Elizabeth was dead and James had been given Berkeley Castle along with most of the entailed lands.