Titanium dioxide (TiO₂) nanoparticles have become an exceptionally effective photocatalyst for the degradation of organic dyes in wastewater treatment. This breakthrough has been related to the distinctive physicochemical features inherent to these nanoparticles. These characteristics include a substantial surface area, remarkable chemical stability, and a potent oxidative capacity upon exposure to ultraviolet (UV) radiation, making TiO₂ a great photocatalyst. This work examines processes involving photocatalytic activity in TiO₂, focusing on the production of reactive oxygen species (ROS) via the formation of electron–hole pairs via photoinduced reactions. This research focuses on significant parameters that affect photocatalytic performance. These factors include particle size, crystal phase (anatase, rutile, or brookite), surface changes, and doping with metals or non-metals to enhance visible light absorption. This paper examines current improvements in TiO₂ nanoparticle production methods and their effects on the effectiveness of photocatalytic processes. An examination of the applications of TiO₂ for the degradation of synthetic dyes, including methylene blue, rhodamine B, and azo dyes, is conducted to highlight its potential to mitigate environmental issues caused by industrial dye pollution. Ultimately, challenges such as the fast recombination of charge carriers and the diminished efficacy of visible light are acknowledged, with several solutions suggested to mitigate these issues. This study seeks to elucidate the function of TiO₂ nanoparticles in dye degradation and to provide a foundation for future research aimed at producing more efficient and ecologically sustainable photocatalytic systems.