The Senior Defense Official/Defense Attaché is the principal military advisor on military issues and developments within Tunisia to the Ambassador, represents the Office of the Secretary of Defense to the government of Tunisia, and is responsible for the overall direction and management of the Defense Attaché Office and the Office of Security Cooperation.  In addition, the Senior Defense Official/Defense Attaché represents the Defense Security Cooperation Agency, the Chairman of the Joint Chiefs of Staff, and other U.S. Department of Defense entities; plans and coordinates U.S. military activities with the Tunisian Armed Forces throughout Tunisia (with U.S. Department of Defense, the Joint Chiefs of Staff, USAFRICOM, and NATO); oversees U.S. military training programs; and supports visits by U.S. Department of Defense, government and military officials.  In addition to the Defense Attaché, the office has a civilian Assistant Attaché, and a U.S. naval attaché.

In addition to the Defense Attaché Office, the Office of Security Cooperation implements the full range of defense cooperation activities in Tunisia.  Chief among these activities is the support of bilateral cooperation programs between Tunisia and the geographic combatant command. Other activities include the sale of defense articles and services; the training and professional development of Tunisian military personnel; and the coordination of humanitarian assistance programs on behalf of the U.S. Department of Defense.