Deputy Under Secretary of Defense (DUSD) is the title for several high-ranking posts in the U.S. Department of Defense, requiring appointment by the president and are confirmed by the Senate by majority vote. There are currently six DUSDs, one for each Under Secretary of Defense.[1] From 2010 until 2017, these positions were known as Principal Deputy Under Secretary of Defense (PDUSD). The title for these positions was renamed to remove the word "Principal" as part of the National Defense Authorization Act for Fiscal Year 2018.[2]
Formerly, there also existed the position of Deputy Under Secretary of Defense (DUSD). Some of these positions require appointment by the president and are confirmed by the Senate by majority vote, while others did not require Senate confirmation. The use of these titles was severely restricted by the FY2010 and FY2011 National Defense Authorization Act (NDAA).