Radiation detectors have gained significant attention due to their extensive applications in high-energy physics, medical diagnostics, aerospace, and nuclear radiation protection. Advances in relevant technologies have made the drawbacks of traditional semiconductor detectors, including high leakage currents and instability, increasingly apparent. Ga₂O₃, diamond, and BN represent a new generation of semiconductor materials following GaN and SiC, offering wide bandgaps of around 5 eV. These ultra-wide bandgap (UWBG) semiconductors demonstrate excellent properties, including ultra-low dark current, high breakdown fields, and superior radiation tolerance, underscoring their promising potential in radiation detection. In this review, we first discuss the materials and electrical properties of Ga₂O₃, diamond, and BN, along with the general performance metrics relevant to radiation detectors. Subsequently, the review provides a comprehensive overview of the research progress in X-ray detection, charged particle detection (e.g., α particles and carbon ions), as well as fast neutron and thermal neutron detection, focusing on aspects such as chip fabrication processes, device architectures, and testing results for radiation detectors based on these three materials.