Darrell Castle (born 1948) is an American political figure, activist and attorney from Memphis, Tennessee, and was the vice presidential candidate of the Constitution Party in the 2008 United States presidential election.

Castle grew up in northeastern Tennessee in a small town near Kingsport. He attended Ketron High School and East Tennessee State University, graduating from each in 1966 and 1970, respectively. At ETSU, he earned a B.S., double-majoring in political science and history.

Castle was then commissioned as an officer in the United States Marine Corps, serving for four years and attaining the rank of First Lieutenant. He cites his military service as fostering his belief that war should not be entered into capriciously nor without congressional approval. After his discharge, he returned to ETSU and began his graduate study of history. He then attended the law school at University of Memphis, then known as Memphis State University, and earned his Juris Doctor in 1979.

Upon receiving his J.D. in Memphis, Castle became an attorney. In 1984, he opened a private firm which later grew into Darrell Castle and Associates. Since then, Castle has opened firms in Milwaukee, Wisconsin; Detroit, Michigan; and Kansas City, Missouri. His firms focus on consumer bankruptcy and personal injury, but also represent clients in the areas of social security/disability and workers' compensation.