Reginald de Braose was one of the sons of William de Braose, 4th Lord of Bramber and Matilda, also known as Maud de St. Valery and Lady de la Haie. Her other children included William and Giles.

The de Braoses were loyal to King Richard I but grew in power under King John of England. The dynasty was in conflict with King John towards the end of his reign and almost lost everything.

Reginald de Braose was a scion of the powerful Marcher family of de Braose, helped manage its survival and was also related by marriage to the Welsh Princes of Wales.