Abstract: To address the challenges of high cutting forces, severe tool wear, and difficulties in surface quality control encountered in conventional turning of nickel-based superalloys, a systematic design and assembly of a three-dimensional ultrasonic-assisted turning (3D UVAT) setup was developed, leveraging the advantages of ultrasonic-assisted machining. Turning experiments on nickel-based superalloy were conducted to investigate the influence of ultrasonic vibration on cutting forces and surface quality during the machining process. The results indicate that the designed 3D UVAT system successfully generates three-dimensional ultrasonic vibrations, with tool-tip amplitudes of 23 μm in the cutting direction, 10 μm in the depth-of-cut direction, and 10 μm in the feed direction. The periodic separation-contact mechanism between the tool and workpiece in 3D UVAT significantly reduces cutting forces by up to 42.6%, while the surface roughness (Ra) decreases by up to 86.3%, compared with conventional turning.