William Bartholomew Giles Egan (December 3, 1824 – November 28, 1878) was a justice of the Louisiana Supreme Court from January 9, 1877, to November 29, 1878.^[1][2]

Born in Amelia County, Virginia,^[3][4] Egan graduated from Emory and Henry College in 1845,^[1][3] and gained admission to the bar shortly thereafter.^[3] He and his family moved to North Louisiana, where Egan "soon acquired a large practice in the Claiborne district".^[3]

In 1857, Egan was elected as a district judge, defeating a popular opponent. He was twice reelected, and after completing his final term returned to private practice.^[3] In 1877, Governor Francis T. Nicholls offered Egan an appointment to the state supreme court, which Egan accepted. Egan remained on the court until his death.^[3] Egan died in New Orleans,^[4] following a rapid decline in health, having previously improved from a period of poor health the previous summer.^[3] He was interred at Oakland Cemetery in Shreveport.^[1]