Royce C. Lamberth (born 1943) is a federal judge in the United States District Court for the District of Columbia.

Lamberth was born in 1943 in San Antonio, Texas. He graduated from the University of Texas and from the University of Texas School of Law, receiving an LL.B. in 1967. He served as a Captain in the Judge Advocate General’s Corps of the United States Army from 1968 to 1974, including one year in Vietnam. After that, he became an Assistant United States Attorney for the District of Columbia. In 1978, Lamberth became Chief of the Civil Division of the U.S. Attorney’s Office, a position he held until his appointment to the federal bench.

He was nominated to the federal bench on March 19, 1987 by President Ronald Reagan, and confirmed by the United States Senate on November 13, 1987. He also served as Presiding Judge of the U.S. Foreign Intelligence Surveillance Court from 1995 to 2002.