Walter FitzOther (fl. 1086; died after 1099) was a feudal baron of Eton  in Buckinghamshire (now in Berkshire) and was the first Constable of Windsor Castle in Berkshire (directly across the River Thames from Eton), a principal royal residence of King William the Conqueror, and was a tenant-in-chief of that king of 21 manors in the counties of Berkshire, Buckinghamshire, Surrey, Hampshire and Middlesex, as well as holding a further 17 manors as a mesne tenant in the same counties.

Origins
In the 11th century, the name FitzOther meant simply son of a man named Other. Historian John Langton Sanford and Alfred Webb stated that Walter was the son of "Lord Otho, an honorary Baron of England, said to have been descended from the Gherardini of Florence"; The Fitzgeralds and Gherardinis are recorded communicating in letters dating back to 1413 between the Tuscany branch and the Earls of Kildare regarding their kinship. In 1507, Gerald FitzGerald, 8th Earl of Kildare, the Viceroy of Ireland, was signing his letters as Gerald, Chief in Ireland of the family of the Gherardini. 

The Fitzgerald's ancestral seat in Florence was referred by English Renaissance poet Henry Howard, Earl of Surrey, in his poem Description and praise of his love, as well as by Medici Florentine Renaissance writer, Cristoforo Landino, on his preface of the Divine Comedy by Dante. Historian J. Horace Round, however, considers this claim to be a fabrication of the fifteenth century.

Marriage and children
He married Beatrice and had issue:

William FitzWalter (died c. 1160), eldest son, 2nd feudal baron of Eton. His son was William de Windsor (died c. 1176), 3rd feudal baron of Eton, who adopted the surname de Windsor. The feudal barony of Eton soon split into moieties between two members of the family, William de Windsor (died 1215/16) and his cousin, Walter de Windsor (died 1203). Walter de Windsor died without children in 1203, when his two sisters became his co-heiresses. The other moiety continued in the descendants of William de Windsor until at least the time of Richard de Windsor, the son of Richard de Windsor (1258–1326).
 Robert FitzWalter, second son, inherited the nearby manor of Eton in Berkshire. 
Gerald de Windsor (c. 1075 – 1135), (alias Gerald FitzWalter), third son, the first castellan of Pembroke Castle in Pembrokeshire (formerly part of the Kingdom of Deheubarth), in Wales, who was in charge of the Norman forces in southwest Wales. He was the progenitor of the FitzGerald, FitzMaurice and De Barry dynasties of Ireland, who were elevated to the Peerage of Ireland in the 14th century and was also the ancestor of the prominent Carew family, of Moulsford in Berkshire, Carew Castle in Pembrokeshire (in the Kingdom of Deheubarth) and of Mohuns Ottery in Devon (see Baron Carew, Earl of Totnes and Carew baronets).
Hugh, lord of the manor of West Horsley, Surrey.

Landholdings as tenant-in-chief
His landholdings as a tenant-in-chief as listed in the Domesday Book of 1086 were as follows (manor, hundred, county):

Buckinghamshire
Eton, Stoke, Buckinghamshire, the probable caput of his feudal barony.
Burnham, Burnham, Buckinghamshire
Hardmead, Moulsoe, Buckinghamshire
Horton, Stoke, Buckinghamshire

Berkshire
[East and West] Hagbourne, Blewbury, Berkshire
Bucklebury Manor, Bucklebury, Berkshire
Kintbury, Kintbury, Berkshire
Chilton, Nakedthorn, Berkshire
Wokefield, Reading, Berkshire
Ortone, Ripplesmere, Berkshire

Middlesex
[East] Bedfont, Spelthorne, Middlesex
Hatton, Spelthorne, Middlesex
Stanwell, Spelthorne, Middlesex
[West] Bedfont, Spelthorne, Middlesex

Surrey
Compton, Godalming, Surrey
Hurtmore, Godalming, Surrey
Peper Harrow, Godalming, Surrey
Kingston [upon Thames], Kingston, Surrey
[West] Horsley, Woking, Surrey

Hampshire
Malshanger, Chuteley, Hampshire
Will Hall, Neatham, Hampshire

Landholdings as mesne tenant
His landholdings as a mesne tenant as listed in the Domesday Book of 1086 were as follows:

Buckinghamshire
Burnham, Burnham, Buckinghamshire
Eton, Stoke, Buckinghamshire
Horton, Stoke, Buckinghamshire

Berkshire
[East and West] Hagbourne, Blewbury, Berkshire
Kintbury, Kintbury, Berkshire
Chilton, Nakedthorn, Berkshire
Ortone, Ripplesmere, Berkshire
Windsor, Ripplesmere, Surrey / Berkshire / Buckinghamshire
Wallingford, Slotisford, Berkshire / Oxfordshire

Middlesex
Stanwell, Spelthorne, Middlesex

Surrey
Compton, Godalming, Surrey
Kingston [upon Thames], Kingston, Surrey
[West] Horsley, Woking, Surrey
Woking, Woking, Surrey

Hampshire
Malshanger, Chuteley, Hampshire
Will Hall, Neatham, Hampshire
Winchfield, Odiham, Hampshire

References

Anglo-Normans
12th-century deaths