Roger Bigod (d. 1107) was a Norman knight who came to England in the Norman Conquest. He held great power in East Anglia, and four of his descendants were Earl of Norfolk.

Roger came from a fairly obscure family of poor knights in Normandy. Robert le Bigot, who was probably Roger's father, acquired an important position in the household of William, duke of Normandy (later William I of England), due, the story goes, to his disclosure to the duke of a plot by the duke's cousin William of Mortain.

Robert or Roger, or perhaps even both, fought at the Battle of Hastings, and afterwards they were rewarded with a substantial estate in East Anglia. The Domesday Book lists Roger as holding 6 lordships in Essex, 117 in Suffolk and 187 in Norfolk.

Bigod's base was in Thetford, Norfolk where he founded a priory later donated to the great monastery at Cluny. In 1101 he furtehr consolidated his power when Henry I granted him licence to build a castle at Framlingham, which became the family seat of power until their downfall in 1307. Two of the places associated with Roger Bigod are Framlingham and Bungay in Suffolk. Framlingham Castle and Bungay Castle were built and improved by successive generations.

In 1069 he, along with Robert Malet and Ralph de Gael (the then Earl of Norfolk), defeated Sweyn I of Denmark near Ipswich. After Ralph de Gael's fall in 1074, Roger was appointed Sheriff of Norfolk and Suffolk, and acquired many of the dispossessed earl's estates. For this reason he is sometimes counted as Earl of Norfolk, but he probably was never actually created earl. He acquired further estates through his influence in local law courts.

In the Rebellion of 1088 he joined other Anglo-Norman barons against William II, who, it was hoped, was to be deposed in favour of Robert Curthose, Duke of Normandy. He seems to have lost his lands after the rebellion had failed, but got them back again.

In 1101 there was another attempt to bring in Robert of Normandy by unseating Henry I, but this time Roger Bigod stayed loyal to Henry.

He died on September 9, 1107 and is buried in Norwich. Upon his death there was a dispute between the Bishop of Norwich, Herbet Losinga and the monks at Thetford, the priory founded by Bigod. The monks claimed that Roger's body, along with those of his family and successors, was due to them as part of the foundation charter of the priory (as was common practice at the time). The issue was apparently resolved when the Bishop of Norwich stole the body in the middle of the night and dragged it back to Norwich.

For some time he was thought to have two wives, Adelaide/Adeliza and Alice de Tosny. It is now believed these were the same woman, Adeliza(Alice) de Tosny(Toeni,Toeny). She was the sister and coheiress of William de Tosny, Lord of Belvoir.

He was succeeded by his eldest son, William Bigod, and, after he drowned in the sinking of the White Ship, by his second son, Hugh Bigod, who later became Earl of Norfolk. He also had 3 daughters: Gunnor, who married Robert, Lord of Rayleigh; Cecily, who married William d'Albini "Brito"; and Maud, who married William d'Albini "Pincerna", earl of Arundel.