Lacy, Walter de (c.1170–1241), lord of Weobley (Herefordshire) and lord of Meath, magnate, was eldest son of Hugh de Lacy (qv) (d. 1186), lord of Meath , and his first wife Rose de Baderon (‘Rose of Monmouth’). He may still have been a minor when his father died (July 1186), as he was not granted his father's lands in England and Normandy till 1189. The lordship of Meath was withheld by John (qv), lord of Ireland, but was restored in 1194 by Richard I after de Lacy supported the king during John's unsuccessful rebellion. In July 1194 he granted a charter to Drogheda, including the customs of Breteuil in Normandy. De Lacy appears to have served as chief governor of the lordship with John de Courcy (qv) in 1194–5, but his conduct was probably unsatisfactory as his lands were escheated (1195) and a fine of 2,100 marks was levied (1198). He made his peace with King John in 1199 and was with him in Normandy in October of that year. He married (a. November 1200) Margaret, daughter of William de Braose (qv). In 1201 he returned to Ireland, where his relations with John de Courcy rapidly turned to antagonism as he supported his brother's campaigns against de Courcy. In the same year he was granted custody of the lordship of Limerick by his father-in-law. In 1203 he joined the expedition led by the justiciar, Meiler fitz Henry (qv), against William de Burgh (qv). His relations with fitz Henry deteriorated from 1205 as fitz Henry implemented the king's policies in Ireland. He joined with William Marshal (qv), earl of Pembroke (d. 1219), against the justiciar, although he did not go into outright rebellion like de Braose. He was summoned to England on pain of forfeiture in April 1207 and eventually was restored to favour. In April 1208 he was granted a new charter for his lordship of Meath and returned to Ireland in June 1208.
De Lacy fell foul of the king in 1210 for giving refuge to de Braose and his family; the king seized his lands in June 1210 and de Lacy went into exile in France. His English lands were restored in July 1213, with the exception of Ludlow castle, which was returned after he served on the king's expedition to France in 1214. His Irish lands, with the exception of the castle of Drogheda, were restored in 1215 after payment of a fine of £4,000. De Lacy remained in England in 1215–16, leaving his half-brother, William, to govern Meath in his place. He supported Henry III during the king's minority and was appointed sheriff of Hereford, a position he held till 1223. He returned to Ireland in 1220 and led an army into Connacht. He returned again in 1224 to deal with the revolt raised by his brother Hugh de Lacy (qv) (d. 1242). As pledge of his good conduct he gave the king the castles of Trim and Ludlow for two years. Despite this, he came under suspicion and his lands were again seized. In May 1225, he regained his lands, but not the castles, after payment of a fine of 3,000 marks. He regained all his lands, castles included, in July 1226, but the liberty of Meath was not restored. He was also given custody of his brother's lands in Ulster for a period of three years, but this custody ended in April 1227 when Hugh de Lacy was restored to the earldom. De Lacy served in France in 1228 and returned to Ireland in 1230 when he joined an expedition to Connacht led by the justiciar, Geoffrey de Marisco (qv). He supported the king against Richard Marshal (qv), earl of Pembroke, in 1234 and joined the expedition to Connacht in 1235. On his death (February 1241), his lordship was divided between his granddaughters Margaret and Matilda, as his son Gilbert had died in 1230, and his grandson Walter, Gilbert's only son, had died in 1238.