PLA/Sisal hybrid composites have been used in cars and technical textile applications. When utilized in composites, 3-D-printed PLA layers can improve performance and homogeneity. The primary goal of this research was to use sisal and 3-D-printed polylactic acid (PLA) layers to develop a sustainable bio-composite. To enhance the bonding of sisal fibres with the PLA matrix, sisal fibres were given a sodium hydroxide treatment. This would improve the mechanical and thermal properties of composites. Sisal fibre (between 4 wt% and 8 wt%), epoxy concentration (between 85 wt% and 90 wt%), and PLA 3-D printing infilling percentage (between 90 wt% and 100 wt%) were the independent parameters. The Taguchi L8 orthogonal array design was used to make the composite samples. The changes in the amounts of PLA infill, epoxy matrix concentration, and sisal fibre content were considered for test sample development. The optimal settings for improving their tensile, flexural, and impact capabilities were determined by analyzing their signal-to-noise ratio (S/N). The PLA/sisal fibre composite showed a remarkable level of mechanical properties in Sample 8, surpassing those of the other samples. To improve mechanical and thermal properties, the appropriate values for sisal fibre composition, PLA infilling percentage, and epoxy concentration percentage were 8 per cent, 95 per cent, and 85 per cent, respectively. After testing, the tensile (293–295.4 Megapascal) (Mpa), impact (2.73–4.84 Mpa), and flexural strength (188.5–270.4 Mpa) results show that the new composite has better mechanical behaviour properties. Additionally, FTIR, SEM, and DSC experiments were run to examine the composite's structural characteristics. Using less volatile epoxy resin, a sustainable 3-D-printed PLA layer and Sisal fibre bio-composite were developed.