Eustace de Montaut, or Monte Alto, Montalt, Monhaut, or FitzNorman (c. 1027 – 1112), was a Breton soldier, and later baron, who fought on the side of the Normans during the Norman Conquest of England in 1066 and for his achievements was granted several manors by the new king, William the Conqueror.

Eustace was born in the early to mid-11th century, possibly in Monthault, Ille-et-Vilaine, Brittany, to parents whose names are not recorded.

Eustace came to England in the years following the Norman Conquest, aiding Hugh Lupus in his conflict with the Welsh.

[2] Eustace united his forces with those of Hugh Lupus, and together succeeded in subduing the Welsh in the county of Flintshire.

[4] Eustace died at an unknown date and was succeeded by his eldest son, Hugh de Montaut.