The 2018 GaN Power Electronics Roadmap, authored by a team of international researchers, highlights the significant potential of Gallium Nitride (GaN) as a compound semiconductor for high-frequency communications and photonic applications. GaN's superior material properties, such as high electric field strength and electron mobility, are driving its commercialization in power conversion applications. The roadmap discusses the advancements in GaN growth on large-area substrates, which are crucial for the technology's commercial viability. It also addresses the challenges and future prospects in GaN technology, including the need for high-voltage breakdown, high-speed switching, and efficient packaging solutions. The paper emphasizes the importance of GaN in emerging markets, such as automotive and electric vehicle charging, and the role of major industrial companies in exploring new circuit topologies and system architectures. The roadmap concludes by outlining the next steps in device research and development, focusing on manufacturing challenges, epitaxial lift-off techniques, and the integration of GaN with other electronic technologies.The 2018 GaN Power Electronics Roadmap, authored by a team of international researchers, highlights the significant potential of Gallium Nitride (GaN) as a compound semiconductor for high-frequency communications and photonic applications. GaN's superior material properties, such as high electric field strength and electron mobility, are driving its commercialization in power conversion applications. The roadmap discusses the advancements in GaN growth on large-area substrates, which are crucial for the technology's commercial viability. It also addresses the challenges and future prospects in GaN technology, including the need for high-voltage breakdown, high-speed switching, and efficient packaging solutions. The paper emphasizes the importance of GaN in emerging markets, such as automotive and electric vehicle charging, and the role of major industrial companies in exploring new circuit topologies and system architectures. The roadmap concludes by outlining the next steps in device research and development, focusing on manufacturing challenges, epitaxial lift-off techniques, and the integration of GaN with other electronic technologies.