Gallium oxide (Ga O ) has gained increased attention for power devices due to its superior material properties and the availability of economical device-quality native substrates. This review illustrates recent advances in Ga O device technologies, beginning with an overview of the social circumstances that motivate the development of new-generation switching devices. Following an introduction to the material properties of Ga O from the viewpoint of power electronics, growth technologies of Ga O bulk single crystals and epitaxial thin films are discussed. The fabrication and performance of state-of-the-art Ga O transistors and diodes are then described. We conclude by identifying the directions and challenges of Ga O power device development in the near future.