Three-dimensional (3D) printing is an emerging technology that could revolutionize manufacturing because of its ability to fabricate complex structures in a simple and cost-effective manner. Although they are great materials for 3D printing, traditional materials do not have high tensile strength or functional properties. Carbon-based nanocomposites have arisen as ideal alternatives to these limitations because of their better mechanical, electrical, and thermal properties. It has evolved in line with the United Nations Sustainable Development Goals (UN SDGs), particularly to encourage sustainable industry and infrastructure (SDG 9). This chapter describes the classification, fabrication processes, and manufacturing of carbon-based nanocomposites for 3D printing. Some carbon-based nanofillers, such as carbon nanofibers, carbon nanotubes, and graphene, have been incorporated into polymeric systems to produce environmentally friendly carbon-based nanocomposite filament outputs for the promotion of sustainable consumption and production (SDG 12). This chapter categorizes the various applications of nanocomposites that are specific to carbon for aerospace, automotive, biomedical, and electronics—helping further promote sustainable urbanization (SDG 11) and cutting-edge clean and other affordable energy (SDG 7). Additionally, issues such as the size, homogeneity, and stability of these materials and future trends in the area are discussed. Ultimately, this will allow excellent 3D printing technologies to be still within the fine line of the UN SDGs where carbon-based nanocomposites can be used.