In this study, the response surface methodology (RSM) technique was applied to model the high-temperature rheological properties of bio-asphalt binders, incorporating crude palm oil (CPO) under unaged and short-term ageing conditions. The interaction effects of CPO at 0, 5, 10 and 15 by weight of the base asphalt binder and test temperatures of 40C- 76C as independent variables on the complex modulus and phase angle were evaluated. Results show that CPO content and test temperature have significant effects on the complex modulus and phase angle of bio-asphalt binders. RSM statistical analyses present high degrees of correlation (R2) of 0.9980, 0.9986, 0.9820 and 0.9682 for the dependent variables' complex modulus and phase angle under unaged and aged conditions, indicating that the developed models are consistent with the experimental results. The numerical optimisation shows that the optimum complex modulus and phase angle of bio-asphalt binders can be achieved with 5 CPO at a temperature of 64C. © 2020 IOP Publishing Ltd. All rights reserved.