The giant planets of the outer Solar System possess complex and dynamic magnetospheric environments shaped by a combination of strong magnetic fields, rapid planetary rotation, internal plasma sources and solar wind coupling. This session aims to bring together observational, theoretical,experimental, and numerical modeling studies focusing on the magnetospheric environments of the outer planets. We invite contributions addressing physical processes across multiple spatial and temporal scales, including but not limited to: magnetic reconnection, velocity shear-driven instabilities, plasma transport, auroral processes, and magnetosphere-ionosphere-thermosphere coupling; radiation belts and energetic particle acceleration and transport; magnetosphere–planet and magnetosphere-moon interactions; moon exosphere generation processes and surface weathering. Comparative studies involving different combinations of outer planet and/or terrestrial magnetospheres are encouraged. Studies involving also asymmetrical/tilted systems (Uranus and Neptune) or exploring links to exoplanetary systems are also very welcome. We encourage submissions leveraging data from past, current, and upcoming space missions (e.g., Juno, Cassini, New Horizons, JUICE, Europa Clipper, and proposed Ice Giant concepts), alongside ground- and space-based observations (e.g., HST, JWST, VLT) and numerical simulations. We particularly encourage contributions from early-career researchers.