An Executive Council (the Council) oversees and administers the activities of the Union between General Assembly meetings. It normally meets at least once per year and every three years for the General Assembly.

The Council is composed of the President, President-Designate, ten Vice-Presidents, the Secretary-General and the Associate Secretary-General, all elected by the General Assembly, plus the immediate Past President. At least one of the members shall be from a developing country. The term of office of Councillors normally begins and ends at the end of each General Assembly. In exceptional circumstances the General Assembly may extend the term of office.

The President may not be re-elected. The President-Designate normally will be elected to the Presidency. Five of the Vice-Presidents shall be elected at large. Five Vice-Presidents shall be elected from among the Chairs of the Commissions. Consideration shall be given to an appropriate sub-disciplinary balance on the Council. If the President is unable to serve, the President-Designate shall assume the Presidency. The Council may fill any other vacancy that occurs between General Assemblies.

The Officers of the Executive Council are those in charge of the daily activities of the Union. To comply with their task they have periodic virtual meetings at least once per month. The current Executive Council Officers are: President, President-Designate, Past President, Secretary General, Associate Secretary General, Deputy Secretary General and the Vice-Presidents at Large for Finance and for the Centenary.