Maud de Lacy, Countess of Hertford and Gloucester

Maud de Lacy, (25 January 1223 – 10 March 1289), was an English noblewoman, being the eldest child of John de Lacy, 2nd Earl of Lincoln, and the wife of Richard de Clare, 5th Earl of Hertford, 6th Earl of Gloucester.

Maud de Lacy had a personality that was described as "highly competitive and somewhat embittered". She became known as one of the most litigious women in the 13th century as she was involved in numerous litigations and lawsuits with her tenants, neighbours, and relatives, including her own son. Author Linda Elizabeth Mitchell, in her Portraits of Medieval Women: Family, Marriage, and Politics in England 1225-1350', states that Maud's life has received "considerable attention by historians".

Maud was styled Countess of Hertford and Countess of Gloucester upon her marriage to Richard de Clare. Although her mother, Margaret de Quincy, was suo jure Countess of Lincoln, this title never passed to Maud as her mother's heir was Henry de Lacy, the son of Maud's deceased younger brother Edmund de Lacy, Baron of Pontefract.

Her eldest son was Gilbert de Clare, 6th Earl of Hertford, 7th Earl of Gloucester, a powerful noble during the reigns of kings Henry III of England and Edward I.

Maud de Lacy was born on 25 January 1223 in Lincoln, Lincolnshire, England, the eldest child of John de Lacy, 2nd Earl of Lincoln, a Magna Carta Surety, and Margaret de Quincy, 2nd Countess of Lincoln suo jure.

Maud had a younger brother Edmund de Lacy, Baron of Pontefract who married in 1247 Alasia of Saluzzo, by whom he had three children.