Pierre Lacau (25 November 1873 – 26 March 1963) was a French Egyptologist and philologist. He served as Egypt's director of antiquities from 1914 until 1936, and oversaw the 1922 discovery of the tomb of Tutankhamun in the Valley of the Kings by Howard Carter.
Pierre Lacau was born in the French commune of Brie-Comte-Robert. He was raised and educated as a Jesuit.
Lacau's first appointment in Cairo was to the International Commission for drafting the general catalogue of the Museum of Cairo.
In 1912 he was appointed director of the French Institute of Eastern Archaeology, succeeding Émile Chassinat, whose work he continued by excavating new structures within Abu Rawash, the funerary complex of Djedefre to the east of the pyramids of Giza.
From 1914 to 1936 he served as director general of the Department of Antiquities of Egypt. He was appointed in 1914 to succeed Gaston Maspero but could not take up the position until after World War I. He immediately announced that excavation concessions would be limited to representatives of public institutions and societies. He then reinterpreted the law covering division of finds so that the Egyptian National Museum could take all unique finds and give the excavator all the rest.