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Office of Secretary of Defense (OSD)


Alternate Definition

The Office of the Secretary of Defense (OSD) is the principal staff element of the Secretary of Defense in the exercise of policy development, planning, resource management, fiscal, and program evaluation responsibilities. OSD includes the immediate offices of the Secretary and Deputy Secretary of Defense, Under Secretaries of Defense, Director of Defense Research and Engineering, Assistant Secretaries of Defense, General Counsel, Director of Operational Test and Evaluation, Assistants to the Secretary of Defense, Director of Administration and Management, and such other staff offices as the Secretary establishes to assist in carrying out assigned responsibilities.
(Sources: https://www.defense.gov/Our-Story/Office-of-the-Secretary-of-Defense/, https://www.defense.gov/Resources)

General Information

The Office of the Secretary of Defense (OSD) is the principal staff element used by the Secretary and Deputy Secretary of Defense to exercise authority, direction, and control over the Department of Defense. The mission of OSD as an organizational entity, in coordination with other elements of DoD, is as follows:


  • Develop and promulgate policies in support of United States national security objectives.
  • Provide oversight to assure the effective allocation and efficient management of resources consistent with Secretary of Defense approved plans and programs.
  • Develop appropriate evaluation mechanisms to provide effective supervision of policy implementation and program execution at all levels of the Department
  • Provide the focal point for departmental participation in the United States security community and other Government activities.


In addition, each OSD principal staff official, in his/her respective area of functional assignment, is responsible for performing the following:


  • Conduct analyses, develop policies, provide advice, make recommendations, and issue guidance on Defense plans and programs.
  • Develop systems and standards for the administration and management of approved plans and programs.
  • Initiate programs, actions, and taskings to ensure adherence to DoD policies and national security objectives, and to ensure that programs are designed to accommodate operational requirements.
  • Review and evaluate programs for carrying out approved policies and standards.
  • Inform appropriate organizations and personnel of new and significant trends or initiatives in assigned areas of functional responsibilities.
  • Review proposed resource programs, formulate budget estimates, recommend resource allocations, and monitor the implementation of approved programs.
  • Participate in those planning, programming, and budgeting activities, which relate to assigned areas of functional responsibilities.
  • Review and evaluate recommendations on requirements and priorities.
  • Promote coordination, cooperation, and mutual understanding within the Department of Defense and between DoD and other Federal agencies and the civilian community.
  • Serve on boards, committees, and other groups pertaining to assigned functional areas, and represent the Secretary of Defense on matters outside the Department of Defense.
  • Develop information and data, prepare reports, and/or testimony for presentations to Congressional Committees or in response to Congressional inquiries.
  • Represent the DoD with Congressional Committees or individual Members of the Congress.
  • Perform such other duties as the Secretary of Defense may from time to time prescribe.