This study investigates the design, processing, 3D/4D printing, and characterization of the novel PETG–PBAT blends. PETG–PBAT blends with 10, 20, and 30 wt% PBAT were prepared via melt mixing. Granules were obtained for 3D printing using a granule-based material extrusion method with a pneumatic system to control melt flow. The results showed that PETG–PBAT blends were immiscible but had good compatibility between phases. Tensile strength and elongation increased and decreased, respectively, with increasing PBAT content. PBAT10% had a tensile strength of 36 MPa and elongation of 51%, which is higher than that of fused deposition modeling (FDM) 3D printing materials. The excellent mechanical properties were attributed to the proper compatibility of the two phases and the control of melt flow and printing parameters. Despite low printability, PBAT30% showed more than 100% elongation and good toughness. The shape memory performance results indicated that increasing PBAT content reduced the transition temperature and strengthened the elastic part, leading to higher shape recovery at a faster rate. The study highlights the potential of PETG–PBAT blends for 3D/4D printing, especially in applications requiring shape memory and biodegradability. Previous studies have shown that PBAT can enhance the mechanical properties of PLA and other polymers, and that compatibilizers can improve the compatibility and mechanical properties of PLA–PBAT blends. The blending of PBAT with other polymers such as PCL, PHBV, PVC, and PPC has also been explored. The results of this study suggest that PETG–PBAT blends have good potential for 3D/4D printing, especially in applications requiring shape memory and biodegradability.This study investigates the design, processing, 3D/4D printing, and characterization of the novel PETG–PBAT blends. PETG–PBAT blends with 10, 20, and 30 wt% PBAT were prepared via melt mixing. Granules were obtained for 3D printing using a granule-based material extrusion method with a pneumatic system to control melt flow. The results showed that PETG–PBAT blends were immiscible but had good compatibility between phases. Tensile strength and elongation increased and decreased, respectively, with increasing PBAT content. PBAT10% had a tensile strength of 36 MPa and elongation of 51%, which is higher than that of fused deposition modeling (FDM) 3D printing materials. The excellent mechanical properties were attributed to the proper compatibility of the two phases and the control of melt flow and printing parameters. Despite low printability, PBAT30% showed more than 100% elongation and good toughness. The shape memory performance results indicated that increasing PBAT content reduced the transition temperature and strengthened the elastic part, leading to higher shape recovery at a faster rate. The study highlights the potential of PETG–PBAT blends for 3D/4D printing, especially in applications requiring shape memory and biodegradability. Previous studies have shown that PBAT can enhance the mechanical properties of PLA and other polymers, and that compatibilizers can improve the compatibility and mechanical properties of PLA–PBAT blends. The blending of PBAT with other polymers such as PCL, PHBV, PVC, and PPC has also been explored. The results of this study suggest that PETG–PBAT blends have good potential for 3D/4D printing, especially in applications requiring shape memory and biodegradability.