William Daniel Quarles Jr. (born 1948) is a United States District Judge on the United States District Court for the District of Maryland.
Born in Baltimore, Maryland in 1948, Quarles received an A.A. from Community College of Baltimore in 1967 and a B.S. from the University of Maryland, College Park in 1976 and a J.D. from the Columbus School of Law at the Catholic University of America in 1979. From 1979 to 1982, Quarles was a law clerk to the Hon. Joseph C. Howard of the U.S. District Court for the District of Maryland. After working in private practice from 1981 to 1982, he joined the U.S. Attorney's Office in Baltimore, MD, where he served as an Assistant United States Attorney until 1986. He reentered private practice at Venable LLP in 1986 and remained with the firm until he became an Associate Circuit Judge for the Circuit Court for Baltimore City in 1996.
Quarles was named to the federal bench by President George W. Bush on January 7, 2003, to a seat vacated by William M. Nickerson. He was confirmed by the United States Senate on March 12, 2003, and received his commission on March 14, 2003.
He is the author of Summary Adjudication: Dispositive Motions and Summary Trials (1991).