Wood and hemp fibres are extensively utilized as reinforcement agents in various construction industries due to their abundant nature and cost-effectiveness. These materials offer a lightweight and eco-friendly alternative to traditional reinforcing materials. Furthermore, Earthen materials, particularly clay, have emerged as green sustainable building materials, attributed to their resource management advantages, environmental benefits (abundance, recyclability, low embodied energy), indoor comfort and positive social impact. Despite these merits, challenges, concerning the load-bearing capacity and durability of 3D-printed earthen structures, persist. Moreover, bridging the gap between the microstructural properties and the macroscopic behaviour of clay composites is a critical hurdle. In this study, we addressed these challenges by assessing the macroscopic behaviour of clay reinforced with wood and hemp fibres. Clay material is reinforced with various proportions of hemp and wood fibres (5%, 10%, 15% and 20% by weight). The individual materials and the different composites are subjected to scanning electron microscopy and Fourier transform infrared spectroscopy for microstructural characterization, followed by mechanical performance investigation through compression and tension tests. Subsequently, the manufacturability of hemp-reinforced clay is evaluated through an additive manufacturing process. The findings reveal similarities and differences in microstructural characteristics of both fibres, leading to a noteworthy increase in clay ductility and tensile strength through the incorporation of 5% of wood and 10% of hemp fibres. Additionally, the successful printability of clay–hemp composite was demonstrated through 3D printing by evaluating the impact of the printing parameters on the final printed structure.