INTOSAI (International Organization of Supreme Audit Institutions) is a professional organization of supreme audit institutions (SAI) in countries members of the United Nations or its specialized agencies. INTOSAI is an autonomous, independent and non-political organization, which is an association of organizations dealing with external state audit. It provides institutionalized framework to supreme audit institutions for developing and transmitting knowledge, development of state audit globally, and strengthening of professional capacities, reputation and influence of member SAIs. SAI have major role in audit of government accounts and operations, and in promoting stable financial management and responsibility in their governments. As citizens, international donors and others have increasingly larger expectations from the national governments, those governments are dependent upon SAI, which help them to ensure public accountability. INTOSAI provides support to their members in achieving this task, by providing the opportunity for exchange of information and experience on audit, assessing challenges they face and understanding the world that keeps changing and becoming increasingly interdependent.

INTOSAI was founded in 1953. From the original 34 member states, membership increased to more than 190 SAIs (currently, INTOSAI has 189 full members and three associate members).

As an internationally recognized leader in public sector auditing, INTOSAI publishes guidelines for financial management and other areas, develops related methodologies, provides training and promotes information exchange among members. INTOSAI has five official languages: Arabic, English, French, German and Spanish.

State Audit Institution of Serbia acquired full membership in INTOSAI in November 2008.