Bone is a vascularized, dynamic tissue that undergoes continuous remodeling. Traumatic injuries often require extended healing, as bone supports locomotion and load-bearing. Conventional treatments, including titanium implants and nano-biomaterials, often fail to mimic native bone due to poor vascularization and structure. Direct ink writing (DIW) 3D printing addresses these gaps by enabling precise deposition of bioinks under favorable conditions, preserving cell viability while offering tunable porosity, mechanical strength, and multi-material integration. It supports the fabrication of personalized, cell-laden scaffolds that mimic native bone architecture and promote osteogenesis. Thus, DIW emerges as a vital, scalable, and versatile platform for advancing functional and clinically relevant bone regeneration strategies. This review highlights advances in 3D printing, particularly DIW, for the design of porous scaffolds and bone-on-a-chip systems with bone-like architecture. We discuss how DIW with nano-biomaterials enhances scaffold geometry, surface properties, and mechanobiology. Finally, we examine cell-material interactions, their underlying molecular mechanisms, and the current challenges and future directions of DIW-printed bone grafts for clinical translation.