<p>3D printing is a quickly developing technique that adds material layer by layer to create the desired shape. Because of its ease of use, additive manufacturing has become increasingly important in the modern manufacturing period. By using this technique, complex and intricate geometries can be produced with much ease in comparison with conventional manufacturing. As the demand for 3D printing continues to rise, the focus on strength, quality, and other mechanical properties is also increasing. Enhancing the properties of the final components can be achieved by incorporating fibers into the base material and developing tailored composite filaments. The primary goal of the ongoing research is the preparation of PETG-CF composite filament using 20% of short carbon fibers to achieve the best mechanical properties such as tensile strength, impact strength and surface roughness. To further enhance the mechanical properties 3D printer input parameters are optimized to the ideal conditions. The considered input parameters are layer thickness, infill density, printing temperature, raster angle, printing speed. Each input parameter is considered at 3 levels. Experiments are designed according to L27 orthogonal array. Experiments are created in the DOE to investigate how different elements affect the process’s performance. Hybrid TOPSIS-Taguchi optimization technique is applied to optimize this multi-objective optimization problem. The findings demonstrate that the ideal sample’s mechanical characteristics are enhanced by 100.522% in the case of tensile strength, 200% in the case of impact strength. Surface roughness value is decreased by 81.59%. From the results, it is identified that infill density and layer thickness are the most influential parameters affecting mechanical properties, while printing speed has the least impact. </p> Graphical abstract <p></p>