A study was conducted to investigate thermoelectric effects (TEEs) in resonant-tunneling magnetic tunnel junctions (RTMTJs) featuring wide-bandgap semiconductors such as ZnO and β-Ga2O3, along with a nonmagnetic metal spacer. The transmission function was determined using the non-equilibrium Green’s function method within a tight-binding model. Significant enhancements in TEEs were observed for the β-Ga2O3 semiconductor compared to other materials, indicating its potential applicability in the emerging field of β-Ga2O3 spincaloritronics.