Walter de Burgh, 1st Earl of Ulster, 2nd Lord of Connaught (English: /dˈbɜːr/; d’-BER; c. 1210 – 28 July 1271) also spelt Burke or Bourke, was an Irish peer from the House of Burgh.

De Burgh was the second son of Richard Mór de Burgh, 1st Lord of Connaught and Egidia de Lacy.

In 1243, he succeeded his father as Lord of Connacht. In a royal order from Westminster in September 1247, Sir John Fitzgeoffrey was charged by the king with seizing the lands of Walter de Burgh's older brother Richard, who had died. The de Burgh lands in Connaught were being held by John de Livet, likely the son of Gilbert de Lyvet, one of the earliest Lord Mayors of Dublin and Marmaduke de Eschales (Scales).

The traditional account that Walter de Burgh became earl of Ulster through marriage to a cousin is no longer generally accepted.^[2][3] According to that account, Walter married a cousin, Lady Maud de Lacy, only daughter and heiress of Hugh de Lacy, 1st Earl of Ulster (by his second wife, Emmeline de Riddlesford, the granddaughter of Walter de Riddlesford). It was asserted that in 1264 De Burgh was created Earl of Ulster in her right.^{[4][5][citation needed]} Walter de Burgh was granted the lands of Ulster in 1263 by Edward, who had been granted Ireland in 1254.^[6][2]

In 1270, he and Walter de Ufford, the Justiciar of Ireland, were defeated by Aedh mac Felim Ua Conchobair at Áth an Chip.

He married Avelina, daughter of Sir John Fitzgeoffrey, Justiciar of Ireland, about 1257.^[2]

He died, aged about 60, in Galway, and was succeeded by his eldest son, Richard Óg de Burgh, 2nd Earl of Ulster ('The Red Earl of Ulster'). Other children were three sons, Theobald, William and Thomas, and a daughter, Egidia, who married Sir James Stewart (1260–1309), 5th High Steward of Scotland.^[7][8]

• House of Burgh, an Anglo-Norman and Hiberno-Norman dynasty founded in 1193
• Lord of Connaught