Reference systems and their standardization are of paramount importance to many fields of astronomy. Some examples are the reduction of ground-based observations, space astrometry, astrophysics missions, and space missions to solar system planetary bodies and beyond.

The concept of a reference system and its realization requires the convergence of reference frames, ephemeris, and time scales to be developed respecting associated standards, thus fulfilling one of the IAU strategic goals as the provider of astronomical standards and their use.

The symposium ADVANCING REFERENCE SYSTEMS, EPHEMERIS AND STANDARDS, supported by the INTERNATIONAL ASTRONOMICAL UNION (IAU), will be a forum to discuss the latest results and prospects in this field as well as to facilitate the coordination of common standards across agencies and organizations.

The symposium will be held in a hybrid format at the National University of La Plata (UNLP) in Argentina, August 4-9, 2025, to promote and strengthen the cooperation between the Latin-American region research community and scientists from other parts of the world. It will also provide an opportunity to stimulate the teaching and learning of astronomy among local communities through the planned educational activities.