William Cushing Wait (December 18, 1860 – January 28, 1935) was a justice of the Massachusetts Supreme Judicial Court from 1923 to 1934. He was appointed by Governor Channing H. Cox. Born in Charlestown, Massachusetts, to Elijah and Eliza Wait, his family moved to Medford, Massachusetts, in 1870, and Wait graduated from Medford High School in 1870. He received his undergraduate degree from Harvard College in 1882, followed by a law degree from Harvard Law School in 1885. He worked in the office of former Boston mayor Nathan Matthews Jr. for a year before entering into a partnership with a Harvard classmate.