Triple oxygen isotope measurements (16O/17O/18O) in O-bearing compounds have become an important part of the geochemical toolkit over the past two decades, influencing various fields such as atmospheric chemistry, meteorites and planetary science, hydrology, paleoclimatology, atmospheric evolution and forensic studies, among other promising applications. This session invites contributions using the 16O/17O/18O isotope system to study modern- and paleo- O-bearing materials, including (but not limited to) waters, ice, sulphates, nitrates, perchlorates, carbonates and silicates. Contributions are welcomed that address analytical methods, theoretical predictions (models), and empirical observations of 16O/17O/18O in water (ice, liquid, vapour) and minerals, with special focus on applications. Presentations discussing technical limitations, analytical improvements, standardization and calibrations to understand kinetic and equilibrium fractionation of 16O/17O/18O are also encouraged. An important goal is to bring together researchers engaged in this field to discuss analytical error, reference materials, reporting of triple oxygen isotope measurements and emerging applications.