This paper presents an experimental investigation on the utilization of recycled Polyethylene Terephthalate (PET) bottle fibers in M35 grade concrete. The increasing generation of plastic waste has become a serious environmental issue due to its non-biodegradable nature and improper disposal methods. The use of recycled PET fibers in concrete offers an effective solution for waste management while enhancing the mechanical properties of concrete. In this study, waste PET bottles were collected, cleaned, and cut into fibers of suitable dimensions before being incorporated into concrete at varying percentages of 0%, 1%, 2%, and 3% by weight of cement. Concrete specimens were prepared and tested to evaluate compressive strength, split tensile strength, and flexural strength after standard curing periods. The experimental results indicated that the inclusion of PET fibers improved the overall performance of concrete by enhancing crack resistance, tensile strength, and flexural behavior. The fibers acted as crack-bridging elements, reducing the propagation of microcracks and improving the ductility of concrete. Among the different mixes, the optimum PET fiber content exhibited the best mechanical performance. The utilization of PET fibers also contributes to sustainable construction practices by reducing plastic waste accumulation and promoting the recycling of non-biodegradable materials. The findings of this study demonstrate that recycled PET fiber reinforced concrete can be considered a viable and eco-friendly construction material. Therefore, the incorporation of PET fibers in concrete not only improves structural performance but also supports environmental sustainability and effective plastic waste management in the construction industry.