Titanium has been the material of interest in biological implant applications due to its unique mechanical properties and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Titanium dioxides (TiO₂) have been very attractive in coating the surface of titanium parts to improve the mechanical, chemical, and biological properties. In this work, TiO₂ nanostructures with anatase, rutile, and mixed phases were successfully synthesized by a controlled pulsed laser-assisted transformation approach on additively manufactured titanium parts. A tunable nanosecond fiber laser with pulse-width duration ranging from 5 to 2000 ns and laser energy in the range of 0.05 to 1.57 mJ was employed for this transformation process. This versatile method is based on the controlled irradiation of titanium surface with a nanosecond fiber laser in the presence of oxygen gas flow. The influence of processing conditions such as laser power, scanning speed, laser pulse duration, frequency, and gas flow on the selective formation of anatase, rutile, and mixed phases was studied. The morphological and structural evolutions were investigated using various characterization techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy methods. The main advantage of this laser-assisted process is its ability to create selective TiO₂ phases on the complex titanium-based bio-implants, including those fabricated by additive manufacturing technologies.