Wide-bandgap semiconductor power devices based on materials such as gallium nitride (GaN), silicon carbide (SiC), and gallium oxide (Ga₂O₃) have gained widespread adoption in power electronics and radio-frequency systems, owing to their high critical electric field, elevated power density, and superior high-frequency performance. However, under high power density operating conditions, power devices experience significant self-heating, which raises the junction temperature and consequently degrades both performance and reliability. Accurate extraction and measurement of the junction temperature are therefore essential for elucidating heat generation mechanisms, optimizing thermal management designs, and enabling reliable lifetime predictions. This review provides a systematic review of the mainstream techniques for junction temperature measurement in wide-bandgap semiconductor devices, categorized into three primary classes: electrical methods, physical contact methods, and optical methods. For electrical methods, the principles underlying temperature-sensitive parameters are introduced, along with their capability for online monitoring. These approaches are particularly well suited for real-time temperature assessment in packaged devices. For physical contact methods, the implementation and measurement principles of techniques such as scanning thermal microscopy and on-chip integrated temperature sensors are evaluated. For optical methods, the principles and application scenarios of non-contact temperature measurement techniques, including infrared thermography, micro-Raman spectroscopy, and thermoreflectance, are analyzed in detail. Finally, the review discusses key challenges currently confronting junction temperature measurements in wide-bandgap devices, including the characterization of ultrafast transient thermal processes, three-dimensional mapping of embedded thermal distributions, and mitigation of strong interference from multiphysics-coupled signals. Prospects for future development are also outlined, encompassing multi-technique fusion approaches, novel deep thermal characterization methods, and the emergence of quantum-precision temperature sensing technologies.