Alix of Brittany, Dame de Pontarcy; Breton noble (d. 1288)
Alix of Brittany, Dame de Pontarcy, Countess of Blois (6 June 1243 – 2 August 1288), was a Breton noblewoman and a member of the House of Dreux as the eldest daughter of John I, Duke of Brittany. She married John I, Count of Blois. Alix was known for founding religious houses including the Monastery of La Guiche, where she was later buried.

Alix, named after her paternal grandmother, Alix of Thouars, was born on 6 June 1243 at the Château de Suscinio in Sarzeau, Morbihan, Brittany. She was the eldest daughter of John I, Duke of Brittany and Blanche of Navarre, daughter of Theobald I of Navarre and Agnes of Beaujeu. Alix held the title Dame de Pontarcy in her own right.

Sometime after a contract was signed on 11 December 1254, she married John I, Count of Blois of the House of Châtillon. Thereafter she was styled Countess of Blois. She brought as her dowry her titles of Pontarcy and de Brie-Comte-Robert, which had been named after her ancestor Robert I of Dreux. The marriage produced one child, a daughter Jeanne, who was heiress to her father's title and estates. In 1270, her husband was appointed Lieutenant General of France.

Through Alix's marriage to John, the Château de Brie-Comte-Robert passed to the Châtillon family.

Alix and John founded several religious houses including the Monastery of La Guiche near Blois in 1277. She became a widow on 28 June 1279. In 1287, the year before her own death, Alix travelled to Palestine. From there she journeyed on to Syria, where she commissioned the erection of two barbican towers at Ptolemais.