United States Assistant Secretary of Defense

Assistant Secretary of Defense is a title used for many high-level executive positions in the Office of the Secretary of Defense within the U.S. Department of Defense. The Assistant Secretary of Defense title is junior to Under Secretary of Defense. Reorganization Plan No. 6 of 30 June 1953 increased the number of assistant secretaries. The National Defense Authorization Act for Fiscal Year 2023 added three new Assistant Secretary positions under the Under Secretary for Research and Engineering. The list of Assistant Secretaries of Defense includes:

• Assistant Secretary of Defense for Acquisition^[1]
• Assistant Secretary of Defense for Critical Technologies^[2]
• Assistant Secretary of Defense for Cyber Policy^[3]
• Assistant Secretary of Defense for Energy, Installations, and Environment
• Assistant Secretary of Defense for Global Strategic Affairs
• Assistant Secretary of Defense for Health Affairs, originally established in 1949 as the Chairman, Armed Forces Medical Policy Council. The position has been abolished and restored several times.
• Assistant Secretary of Defense for Homeland Defense and Hemispheric Affairs, established in 2003
• Assistant Secretary of Defense for Indo-Pacific Security Affairs^[4]
• Assistant Secretary of Defense for Industrial Base Policy^[5]
• Assistant Secretary of Defense for International Security Affairs
• Assistant Secretary of Defense for Legislative Affairs
• Assistant Secretary of Defense for Manpower and Reserve Affairs, mandated by the Department of Defense Authorization Act of 1984 (P.L. 98-94, passed 24 September 1983).
• Assistant Secretary of Defense for Mission Capabilities.^[2]
• Assistant Secretary of Defense for Nuclear, Chemical, and Biological Defense Programs^[6]
• Assistant Secretary of Defense for Readiness^[7]
• Assistant Secretary of Defense for Research and Engineering / Chief Technology Officer
• Assistant Secretary of Defense for Science and Technology^[2]
• Assistant Secretary of Defense for Special Operations/Low Intensity Conflict & Interdependent Capabilities
• Assistant Secretary of Defense for Strategy, Plans and Capabilities^[8]
• Assistant Secretary of Defense for Sustainment^[9]

The deputy to an Assistant Secretary of Defense has the title Deputy Assistant Secretary of Defense.

Former Assistant Secretary of Defense positions include:

• Assistant Secretary of Defense for Public Affairs, originally established as the Assistant to the Secretary (Director, Office of Public Information) by Secretary James V. Forrestal in July 1948.
• Assistant Secretary of Defense for Networks & Information Integration
• Assistant Secretary of Defense for Internal Communications