Polyvinyl alcohol (PVA) and various concentrations of (5–25 wt%) alkali treated Limonia acidissima shell powder (LASP) was utilized to develop bio composite packaging films by solution casting method. The alkali treatment (5%NaOH) of the LASP particles were carried out to improve the interface adhesion between filler and PVA matrix and also remove non cellulosic contents from LASP. The biofilms were characterized by Fourier‐transform infrared spectroscopy, X‐ray diffraction analysis, thermogravimetric analyzer, field emission scanning electron microscopy, Tensile test, UV–vis spectroscopy analysis, water uptake, water vapor permeability, and soil burial test. The bio composite films reinforced with alkali treated LASP particles and compatibilized matrix lead to notable increase in the mechanical, optical, and biodegradation properties when compared to the neat PVA film. The increase in thermal stability (13.49%) of (332.06°C) PVA/alkali‐treated LASP biofilm compared to that of pure PVA film (287.24°C). Tensile stress and young's modulus were enhanced to 57.03% and 83.35%, respectively, with the inclusion of alkali‐treated LASP (up to 20 wt%) in PVA film. Scanning electron microscope micrographs showed that, beyond the 20 wt% of the filler the irregularities emerged on the surface of the biofilms, consequently the mechanical and water barrier properties were diminished However, the PVA/alkali‐treated LASP biofilms absorb less water than pure PVA films. The increased water transport with in the films facilitated the biodegradation behavior (32.11% of weight loss in soil) of composite film. Hence the results suggested the composite films developed in the study to be an ideal material for packaging and cosmetics industries as well as adding the value to wood apple (Limonia acidissima) waste.