Maurice fitz Maurice (1238 – before 10 November 1286) was an English magnate in Ireland, soldier, and Justiciar of Ireland from 1272 to 1273.
He was born in 1238 in Wexford, Ireland, one of the sons of Maurice FitzGerald, 2nd Lord of Offaly and Juliana, whose surname is unknown. He had three brothers, Gerald fitz Maurice II (died 1243), Thomas fitz Maurice (died 1271), David fitz Maurice (died without issue). Maurice was known by the nickname of Maurice Mael (in English bald). He was granted his father's lands in Connacht in exchange for quitclaiming the barony of Offaly before 20 May 1257, when his father Maurice fitz Gerald II died at Youghal Monastery. Before his father died, Maurice was custos of Offaly, but after Maurice fitz Gerald II died, the countess of Lincoln, Margaret de Quincy, sued him for custody of Offaly. The next lord of Offaly was Maurice's nephew Maurice fitz Gerald III, son of his elder brother, Gerald fitz Maurice II who had died in 1243. Maurice fitz Gerald III must have been born within nine months of his father's death. Once his nephew was 'full-age', Maurice fitz Maurice and Maurice fitz Gerald III captured the justiciar, Richard de la Rochelle, Theobald Butler IV, and John de Cogan I (whose son was married to Maurice fitz Gerald III's sister, Juliana). The capture of the three magnates led to a private war in Ireland, with the Geraldines on one side and Walter de Burgh and Geoffrey de Geneville on the other. However, the Second Barons' War in England forced them to come to a temporary peace while they battled Montfortians in the English Midlands in 1266. Maurice III, drowned in the Irish Channel in July 1268, was the 3rd Lord of Offaly, and was succeeded by his own son, Gerald fitz Maurice III (born in 1263). Gerald's marriage was sold to Geoffrey de Geneville, who matched Gerald with his own daughter, Joan, but he died childless on 29 August 1287.
In May 1265, Maurice fitz Maurice was among the chief magnates in Ireland summoned to inform King Henry III of England and his son Prince Edward about conditions in the country, and again in June 1265. These were the result of the private war between the Geraldines (Maurice and his nephew, Maurice fitz Gerald III) and Walter de Burgh, lord of Connacht (who was later made the 1st earl of Ulster). Maurice was appointed Justiciar of Ireland on 23 June 1272 following the accidental death of his predecessor, James de Audley on 11 June of that year; his father had served in the same capacity from 1232 to 1245. Maurice himself held the post until September 1273, when he was succeeded by Sir Geoffrey de Geneville, Seigneur de Vaucouleurs.
He held four knight's fees in both Lea and Geashill from Roger Mortimer, 1st Baron Mortimer who had inherited them from his wife, Maud de Braose.
In 1276, he led a force of men from Connacht against the Irish of County Wicklow. Maurice's contingent joined the main army of English settlers jointly commanded by his son-in-law, Thomas de Clare, Lord of Inchiquin and Youghal who had been made Lord of Thomond earlier that same year, and Sir Geoffrey de Geneville, Maurice's successor as Justiciar of Ireland. The English under Thomas de Clare and Geoffrey de Geneville attacked the Irish at Glenmalure, but were defeated and suffered heavy losses.
Sometime between May 1258 and 28 October 1259, he married his first wife, Maud de Prendergast, daughter of Sir Gerald de Prendergast of Beauvoir and an unnamed daughter of Richard Mor de Burgh. Together he and Maud had one daughters:Amabel FitzGerald, married but died childless.
Maurice was Maud's third husband. She died on an unknown date. In 1273, Maurice married his second wife, Emmeline Longespee (1252–1291), daughter of Stephen Longespee and Emmeline de Ridelsford. He and Emeline had one daughter.Juliana FitzGerald (d. 24 September 1300), married firstly, Thomas de Clare, Lord of Thomond, by whom she had four children; she married secondly Nicholas Avenel, and thirdly, Adam de Cretynges.
Maurice died sometime before 10 November 1286 at Ross, County Wexford. Emmeline Longespee then fought until her death to claim her dower against her daughter, Juliana, her step-daughter, Amabilia, and John FitzGerald, who would be created 1st Earl of Kildare on 14 May 1316. John was the son of his brother Thomas by Rohesia de St. Michael. John sued or physically took lands from the bailiffs of Emmeline, Juliana, and Amabilia.