Bioplastics are an alternative to conventional plastics that have been used in society. The advantage of bioplastics is that they are easily degraded in nature because they come from easily renewable materials such as starch which comes from plants. However, biodegradable plastics have shortcomings in terms of tensile strength so that additional supporting materials are needed in their manufacture. Optimization using the Response Surface Methodology (RSM) central composite design (CCD) in this study aims to obtain optimal mechanical properties (tensile strength). The independent variables used in this study include ZnO concentrations (3%, 6%, and 9%) and glycerol concentrations (2 ml, 5 ml, and 8 ml) as well as mechanical properties such as tensile strength and elongation in response. The optimum conditions were obtained at a concentration of ZnO 6.99% and glycerol 5.32 ml with a tensile strength value of 1.58456 MPa and 9.082201% elongation.