Abstract Power semiconductor devices are fundamental drivers for advances in power electronics, the technology for electric energy conversion. Power devices based on wide-bandgap (WBG) and ultra-wide bandgap (UWBG) semiconductors allow for a smaller chip size, lower loss and higher frequency compared with their silicon (Si) counterparts, thus enabling a higher system efficiency and smaller form factor. Amongst the challenges for the development and deployment of WBG and UWBG devices is the efficient dissipation of heat, an unavoidable by-product of the higher power density. To mitigate the performance limitations and reliability issues caused by self-heating, thermal management is required at both device and package levels. Packaging in particular is a crucial milestone for the development of any power device technology; WBG and UWBG devices have both reached this milestone recently. This paper provides a timely review of the thermal management of WBG and UWBG power devices with an emphasis on packaged devices. Additionally, emerging UWBG devices hold good promise for high-temperature applications due to their low intrinsic carrier density and increased dopant ionization at elevated temperatures. The fulfillment of this promise in system applications, in conjunction with overcoming the thermal limitations of some UWBG materials, requires new thermal management and packaging technologies. To this end, we provide perspectives on the relevant challenges, potential solutions and research opportunities, highlighting the pressing needs for device–package electrothermal co-design and high-temperature packages that can withstand the high electric fields expected in UWBG devices.