Natural fiber extracted from Plantain (Musa paradisiaca) fibers were treated with potassium permanganate (KMnO₄)—acetone solution at various concentrations for different soaking time. In order to identify the effect of this chemical modification on the macromolecular, morphological, crystallographic structures and thermal properties of the fibers, X-Ray Diffraction (XRD), Fourier Transform Infra-red (FTIR), Thermogravimetric analysis (TGA) and Scanning Electron Microscope (SEM) was used.  Wide angle X-Ray Diffraction analysis shows a significant change in the macromolecular and the crystallographic parameters of the fiber, Fourier Transform Infra-red (FTIR) spectral confirm the partial removal of wax, hemicellulose, and lignin content. Thermogravimetric analysis (TGA) shows that thermal stability of the fibers increases after treatment, while Scanning Electron Microscope (SEM) micrographs indicate enhance surface roughness of treated fibers. Treated Fibres with 0.05% KMnO₄-acetone solution for 3min (05K3) was found to have the highest degree of crystallinity, bulk density, enhance surface roughness, good thermal stability and crystallite size.