This study presents a sustainable method for 3D printing wood using a water-based ink composed of lignin and cellulose, the primary components of natural wood. The ink is formulated to mimic the structural and mechanical properties of natural wood, enabling the creation of complex wood structures through direct ink writing (DIW). After heat treatment, the printed structures closely resemble natural wood in appearance, texture, olfactory characteristics, and mechanical properties. The process allows for the recycling of waste wood, offering a sustainable pathway for wood utilization. The ink is made from cellulose nanocrystals (CNCs), tempo-oxidized cellulose nanofibers (TOCNs), and hardwood lignin. The ink's rheological properties are optimized for DIW, allowing for high-resolution printing. The printed structures are then heat-treated to enhance their mechanical properties and structural integrity. The heat treatment causes lignin to act as a molecular glue, binding the cellulose-based components into a cohesive structure. The study demonstrates that the 3D-printed wood has similar thermal stability to natural wood, with both materials undergoing thermal degradation around 250°C. The mechanical properties of the 3D-printed wood are comparable to those of natural wood, with double-pressed samples showing significantly enhanced compressive and flexural strength. The 3D-printed wood also exhibits a macroscopic anisotropy, similar to natural wood, while maintaining a nanoscale isotropic structure. The results show that the 3D-printed wood can be used for various applications, including decorative, recreational, and disposable utensils. The study highlights the potential of using nanoscale building blocks from waste wood to create sustainable, functional, and structurally robust 3D-printed wood structures. The process is recyclable and sustainable, with the potential for further enhancement through the incorporation of additional fibers and reinforcements into the ink formulation. The study also suggests that the ink components can be sourced from other low-cost green resources, expanding the possibilities for sustainable wood printing.This study presents a sustainable method for 3D printing wood using a water-based ink composed of lignin and cellulose, the primary components of natural wood. The ink is formulated to mimic the structural and mechanical properties of natural wood, enabling the creation of complex wood structures through direct ink writing (DIW). After heat treatment, the printed structures closely resemble natural wood in appearance, texture, olfactory characteristics, and mechanical properties. The process allows for the recycling of waste wood, offering a sustainable pathway for wood utilization. The ink is made from cellulose nanocrystals (CNCs), tempo-oxidized cellulose nanofibers (TOCNs), and hardwood lignin. The ink's rheological properties are optimized for DIW, allowing for high-resolution printing. The printed structures are then heat-treated to enhance their mechanical properties and structural integrity. The heat treatment causes lignin to act as a molecular glue, binding the cellulose-based components into a cohesive structure. The study demonstrates that the 3D-printed wood has similar thermal stability to natural wood, with both materials undergoing thermal degradation around 250°C. The mechanical properties of the 3D-printed wood are comparable to those of natural wood, with double-pressed samples showing significantly enhanced compressive and flexural strength. The 3D-printed wood also exhibits a macroscopic anisotropy, similar to natural wood, while maintaining a nanoscale isotropic structure. The results show that the 3D-printed wood can be used for various applications, including decorative, recreational, and disposable utensils. The study highlights the potential of using nanoscale building blocks from waste wood to create sustainable, functional, and structurally robust 3D-printed wood structures. The process is recyclable and sustainable, with the potential for further enhancement through the incorporation of additional fibers and reinforcements into the ink formulation. The study also suggests that the ink components can be sourced from other low-cost green resources, expanding the possibilities for sustainable wood printing.