David William Marsden (born April 5, 1948) is an American politician of the Democratic Party. In 2010 he was elected to represent the 37th district, a portion of Fairfax County, in the Senate of Virginia, and later re-elected to the senate. Between 2006 and 2010, he served in the Virginia House of Delegates representing the 41st district. Prior to his career in politics he spent 17 years as head of the Fairfax County Juvenile Detention Center until 1999. In 2000 Governor Jim Gilmore appointed him Chief Deputy and then Acting Director of the 2,700-person Virginia Department of Juvenile Justice. He then served for 6 months in the administration of Governor Mark Warner.

On January 12, 2010, Marsden defeated Steve Hunt in a special Senate election to replace Republican Ken Cuccinelli who was elected Attorney General the previous fall. On January 13, 2010, Marsden was sworn in. An additional special election was held March 2, 2010 to replace Marsden in the Virginia House of Delegates. It was won by Democrat Eileen Filler-Corn.

David W. Marsden graduated from W.T. Woodson High School in 1966 and Randolph-Macon College in 1970.