The low thermal conductivity of ultrawide bandgap (UWBG) gallium oxide (β-Ga₂O₃) is the most significant bottleneck restricting the development of its power devices, posing a huge challenge for efficient heat dissipation under high-power density conditions. Therefore, developing new thermal management and packaging technologies is extremely urgent. It is crucial to alleviate the performance and reliability issues caused by self-heating through thermal management at the material, device, and packaging levels. This paper provides a timely review of the state of the art in thermal management of UWBG β-Ga₂O₃ power devices, discussing related challenges, potential solutions, and research opportunities. The paper firstly introduces the characteristics of UWBG β-Ga₂O₃ and its significance in electronic devices, and elaborates on the crucial firstly importance of thermal management in β-Ga₂O₃ devices. Then, various thermal management techniques, including substrate-related methods and junction-side thermal management techniques, are thoroughly examined, and their impact on the electrical properties of β-Ga₂O₃ devices is analyzed. Finally, the future development trends of thermal management for UWBG β-Ga₂O₃ devices are prospected. Multi-dimensional thermal management strategies are proposed, focusing on “material-device-packaging” electrothermal collaborative design, near junction heterogeneous integration, and novel external packaging, aiming to arouse relevant research and accelerate the development and industrialization process of UWBG β-Ga₂O₃ power devices.