This study aimed to examine the structural, mechanical, thermal and barrier properties of the polyvinyl alcohol/casein (PVA/CA) films plasticized with poly(ethylene glycol) (PEG) and sorbitol (SOR). The films were prepared by solution casting technique at different loading levels of plasticizers (10-15-20-25%). The mechanical results indicated that PEG and SOR effectively plasticize the PVA/CA film while SOR efficiency was higher than PEG. The addition of plasticizers decreased the tensile strength while the increased elongation at break value of PVA/CA film. The maximum tensile strength was observed in 10% PEG addition as 37.5 MPa. On the other hand, maximum elongation at break value was observed in 15% SOR at 369% that was higher than the un-plasticized film about 58%. The water contact angle measurements showed that all films were hydrophilic structures (32-75 degrees). Also, the water vapour permeability of the un-plasticized film was measured as 6.4 g m(-1) s(-1) Pa-1 x 10(-11). This value decreased with the addition of PEG (5.5 g m(-1) s(-1) Pa-1 x 10(-11)) while increasing SOR addition (12.2 g m(-1) s(-1) Pa-1 x 10(-11)). The thermal degradation temperature of un-plasticized PVA/CA film was decreased with plasticization. The residual weight of un-plasticized PVA/CA was 12.5 wt. %, which decreased at 4.5 wt. % for PEG-25 and 4.8 wt. % for SOR-20 films. Also, the melting temperature of the films decreased by increasing the content of plasticizers. Melting temperatures of SOR containing films were lower than PEG containing the films. Consequently, un-plasticized and plasticized PVA/CA-based films successfully prepared and analyzed to determine the appropriate plasticizer. All prepared films exhibited acceptable properties for use as food packaging or biobased materials.