The emerging electromagnetic and optoelectronics problems involve the multiphysics process, such as nonlinear and quantum plasmonic, light-to-electricity conversion, optical-thermal process. This special issue aims to bring together with the lasted research on the multiphysics in EM and optoelectronics from theory, modeling to application. The topics of this session focuses on simulation techniques in FDTD, MoM, TDIE, FEM, DGTD, DDM, and other hybrid method etc. for multiphysics and multiscale problems; Nonlinear and nonlocal response in electromagnetic, quantum plasmonic effect, plasmonic-thermal and plasmonic-electrical effect; theory, modeling and application of multiphysics process in optoelectronics e.g. perovskite (organic) based solar cells, light emitting diodes and photodetectors; Engineered materials e.g. metamaterials and topological insulators.