Walter FitzAllan (1106 – June 1177) was the first Hereditary High Steward of Scotland (c. 1150-1177), and described as "a Norman by culture and by blood a Breton". He was the third son of a Breton knight, Alan fitz Flaad, feudal lord of Oswestry, by his spouse Aveline, daughter of Ernulf de Hesdin.
When The Anarchy took hold in England and civil war between Empress Matilda and Stephen, Walter rallied to the support of the Empress.
When Empress Matilda's cause was lost, Walter befriended David I who was an uncle of Matilda. He became David's dapifer or Steward. Accompanied by his brother Simon, Walter came to Scotland about 1136 and fought for Scotland at the Battle of the Standard at Northallerton in 1138 under the command of David I's son, Prince Henry.
Subsequently he was appointed Steward of Scotland by King David I; in 1157 the appointment as Steward was confirmed as a hereditary office. In return for the service of five knights, David also granted him what eventually comprised Renfrewshire: the lands of Paisley, Pollok, Cathcart, and Ayrshire; this grant was reconfirmed in a charter in 1157 from Malcolm IV. In 1163 Walter founded, first at Renfrew but shortly afterwards at Paisley, a house of monks of the Cluniac order drawn from the priory of Much Wenlock, in his native county of Shropshire. Walter acquired directly from the Crown the Berwickshire estates of Birkenside and Legerwood on the eastern or left bank of the Leader Water and presented to the monks the church of Legerwood, which they held from 1164 until the Reformation in 1560. The monastery steadily grew and by 1219 became Paisley Abbey.