ConspectusGraphene, a groundbreaking two-dimensional (2D) material, has attracted significant attention across various fields due to its exceptional properties. However, 2D graphene sheets tend to restack or agglomerate, reducing their performance and active surface area. To overcome these limitations and expand graphene’s potential applications, researchers have developed three-dimensional (3D) graphene structures with diverse architectures, including 3D graphene fibers, foams, aerogels, hydrogels, tubes, and cages. These structures, along with modifications such as functionalization, doping, preintercalation, and compositing, prevent stacking and enhance specific properties for targeted applications.3D graphene’s high surface area, mechanical stability, lightweight nature, and abundant active sites make it ideal for applications requiring superior optical properties, thermal and electronic conductivity, and structural stability. Additionally, its unique architecture and chemical modifications facilitate efficient electron, ion, and mass transport. This makes 3D graphene highly suitable for various applications, including batteries, solar cells, supercapacitors, water splitting, and solar desalination.Despite these advancements, further improvements are needed to enhance the commercial feasibility and adaptability of 3D graphene. A deeper understanding of how synthesis techniques and chemical modifications influence its properties is crucial, as current knowledge remains limited. Achieving precise control over its properties during the transition from 2D graphene or polymers to 3D graphene also remains a significant challenge. Additionally, while graphene prices have decreased over the years, it remains relatively expensive compared to alternative materials, and scaling up production while maintaining high quality continues to be a major barrier.In this Account, we provide a comprehensive analysis of various synthesis methods and chemical modifications of 3D graphene, emphasizing its transformative potential across energy storage, energy conversion, and environmental applications. We explore a range of chemical strategies, including the manipulation of structural building blocks, preintercalation, doping, compositing, functionalization, and synthesis, and their effects on different applications. By highlighting recent advancements in 3D graphene research and addressing the challenges hindering its commercial adoption, we aim to underscore its significance and the critical challenges that remain in its development and application within materials science and engineering.