3D printing has transitioned from the commercial and educational sectors to become a tool for materials science. The technologies available for 3D printing have evolved rapidly, facilitating the incorporation of new materials and functionalities into filaments and resins. As the cost of 3D printing decreases and the technologies supporting high-resolution printing become industry standards, the push toward 4D printing, a subcategory of 3D printing that enables the fabrication of components through multiple techniques and materials, will transform the energy sector. 3D printing is no longer limited to plastics; material blends that include metals, graphene, and hybrid architectures for electrode applications are now possible. Energy storage and fuel cells have advanced through 3D printing-assisted methods for prototyping and evaluating innovative designs and compositions. This chapter describes the techniques used to develop 3D-printed batteries, examining the limitations of extrusion-based printing and new approaches to provide lightweight, high-capacity, ergonomically designed batteries. This chapter also explores the development of 3D-printed devices for wearable energy storage, with a focus on nanomaterials that have the potential to transform 3D-printed energy-based applications. The chapter will conclude with an overview of emerging technologies and the impact of additive manufacturing techniques on the design of fuel cells and photovoltaics. The methods detailed in this chapter provide an introduction to the principles of energy-based applications supported by 3D printing and the design, fabrication, and tailoring of those applications. Further comprehensive information can be found in the references attributed to this chapter.