The United Services Institute of the Australian Capital Territory (USI-ACT) is an organisation that aims to promote understanding of national security and defence issues. It serves as a forum where members and guests can be informed on these subjects through lectures and presentations from a range of distinguished speakers.

USI-ACT offers a program of activities designed to meet its objectives, including presentations from subject matter experts covering a broad range of topics spanning regional and global issues during formal and informal social settings. USI-ACT membership provides opportunities for networking across government, military and industry. Membership is open to anyone with an interest in national security and defence. Institute members enjoy a range of benefits, including subsidised and catered events.