The thermal and mechanical properties of locally available bio-extracted banana fiber reinforced polypropylene commingled composite systems were studied. An entirely new method was adopted for the extraction of banana fiber, which is through an anaerobic process. The thermal properties of the commingled composite (both treated and untreated) were analyzed using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed an improved thermal stability for the treated composites. A noticeable increase is observed in the hardness and tensile properties of the treated samples compared to the untreated ones while a decrease is observed for the impact properties of the treated samples. The surface morphology and fiber treatments were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy.