The present study described the experimentation and modeling of supercritical CO2 extraction (SCE) process for papaya seed oil. Experiments were performed at various ranges of SCE parameters; temperature (303.15-368.15) K, pressure (15-35) MPa, solvent flow rate (5-25) g/min, particle size (0.2-1.4) mm and co-solvent (ethanol) flow rate as (0-20)% of CO2 flow rate. Obtained oil was analyzed through gas chromatography to estimate fatty acid concentrations. Effects of SCE parameters were investigated on the extraction yield and oleic acid concentration of papaya seed oil through central composite design. Further, two mathematical models (PM-1 and PM-2) were developed based on desorption-diffusion-dissolution (PM-1) and broken and intact cell (PM-2) mechanisms. These models were validated with the experimental data of papaya seed oil and further compared with the existing models. PM-1 proposed an equilibrium relation while assuming saturation of solvent and solute at interphase, which was successfully validated with the experimental data in the AARD range from 0.40% to 32.48%. PM-2 reduced the three zones of extraction curves to two and better fitted the experimental data of papaya seed in the AARD range from 0.45% to 35.62%. Model parameters of PM -2 were optimized through genetic algorithm. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.