William Francis Riordan (March 26, 1941 – November 16, 2020) was an American jurist who served as a justice of the New Mexico Supreme Court from 1981 to 1986, serving most of his final year on the court as chief justice.

Riordan was born in Wichita, Kansas, and grew up in Albuquerque, New Mexico.

[1][3][2] Riordan was elected to the New Mexico Supreme Court in 1980 as a Republican, defeating incumbent Democratic Justice Edwin L. Felter,[4] and served from January 1, 1981, to December 31, 1986.

[6] Under his tenure as chief justice, the court undertook several projects in a short period of time, including mandating continuing legal education for the state bar, establishing an attorney's specialization program, implementing a new code of ethics, and recodification of the Supreme Court's rules.

[3] From January through March 1987, he served as acting Secretary of Corrections for New Mexico, and as Independent Counsel for the City of Albuquerque from 1987 to 1990.