Robert is said to have married twice: (1) Agnes, daughter of Geoffrey Bainard, Sheriff of York and (2) Agnes, daughter and heiress of Fulk de Paynel of Carleton, North Yorkshire.[11][12] Farrer mentions both marriages and in particular points out that the superior of Carleton Manor was de Brus, and that Paynel held it of him.
It is unclear by which spouse his sons were but authorities usually give her as Agnes de Paynel.
Adam de Brus (1), eldest son and heir upon whom devolved, under feudal law, all the English estates.[13] he only survived his father by 12 months, having married Jueta, daughter and heiress of William de Arches. She outlived her husband by decades, dying just after 1202.[14]
Robert de Brus, the younger son, upon whom his father had settled the Scottish Lordship of Annandale, plus several wheat-producing ploughates at Skelton, Yorkshire, in his lifetime.[15]