The geodynamics of Southeast Asia presents a wide range of processes operating both at Earth’s surface and Earth’s deep interior, which together have shaped the evolution of our planet since the onset of plate tectonics. These processes include continental rifting and marginal basin rifting, long- to short-lived oceanic subduction, arc- and plume-related magmatism, collisional orogeny, and arc accretion. Many of these processes are ongoing today or were active during the Cenozoic, providing opportunities for detailed study. Main unknowns on the geodynamics of SE Asia include questions on the reconstruction of the proto-South China Sea plate, paleo-Pacific subduction, and proto-Philippines Sea plate as well as the connection with the Tethyan realm to the south, the collision of Australian-derived fragments in eastern Indonesia and associated extension processes. To address these issues, we invite contributions from across the Earth sciences, including field-based geology, geochronology, geochemistry of detrital minerals and magmas, seismology, geodynamic and thermo-mechanical modeling, and plate kinematic and tectonic reconstructions.