ABSTRACTInvestigating the mechanical and wear properties of widely used PETG (polyethylene terephthalate glycol) filaments is important to understanding the material's performance, reliability, and suitability in different application areas. This study performed tensile and wear tests on PETG samples produced with a 3D printer using four infill patterns (honeycomb, grid, triangular, and gyroid). The study aimed to investigate the effect of infill patterns on the tensile and wear properties of the samples. In the evaluations, friction coefficient, wear rate, SEM microscope images, hardness test, temperature measurement during tensile, diameter accuracy value, Young's modulus, and yield values were analyzed. The mechanical results present that the triangular pattern showed 133% higher mechanical strength compared to other patterns with the highest Young's modulus. As a result of the wear tests, horizontal patterns showed more homogeneous wear, while vertical patterns caused irregular wear by creating more brittle structures. It was found that dense patterns, such as honeycomb and grid, were more resistant to wear. The triangular pattern samples can be preferred for high strength and thermal stability, while gyroid and grid pattern samples can be used in the flexibility field. The results revealed that different infill patterns significantly affect the mechanical and tribological performances of the materials and that appropriate pattern selection can optimize performance in engineering applications.