Office of the Secretary of Defense

The Office of the Secretary of Defense (OSD) is a headquarters-level staff of the United States Department of Defense. It is the principal civilian staff element of the U.S. secretary of defense, and it assists the secretary in carrying out authority, direction, and control of the Department of Defense in the exercise of policy development, planning, resource management, fiscal, and program evaluation responsibilities. OSD is the secretary of defense's support staff for managing the Department of Defense, and it corresponds to what the Executive Office of the President of the U.S. is to the U.S. president for managing the whole of the Executive branch of the federal government. As of March 2026 the Secretary of Defense is Pete Hegseth. Since 2025 the secondary title "Office of the Secretary of War" (OSW) is a secondary name, permitted only in ceremonial and non-statutory contexts.