William Bayard Shields (1780 - April 19, 1823) was a United States federal judge.
Born in Maryland in 1780, Shields read law to enter the bar. He began a private practice in Wilmington, Delaware, which he continued until 1802, when he became Secretary of State of Delaware. He was in private practice in Natchez, Mississippi from 1803 to 1809, and was a U.S. agent to adjust land claims west of the Pearl River in 1804, and a member of the Mississippi Territorial Legislature from 1808 to 1809. He served as attorney general of Mississippi Territory beginning in 1809, but returned to private practice in Natchez by 1812. He was again in the Mississippi Territorial Legislature from 1813 to 1814, returning to private practice in Natchez from 1814 to 1817. He was a judge on the Mississippi Superior Court from 1817 to 1818.
On April 20, 1818, Shields was nominated by President James Monroe to a new seat on the United States District Court for the District of Mississippi created by 3 Stat. 413. He was confirmed by the United States Senate on April 20, 1818, and received his commission the same day, serving thereafter until his death, in 1823, in Natchez.