© 2021 Wiley Periodicals LLC.Phenolic compounds from olive leaves, which attract great attention with their high phenolic content and high antioxidant activity, need to be dried to increase the extraction efficiency before extraction. For this purpose, it is aimed to obtain optimal drying conditions of hot air inlet temperature (Tg), orifice inlet air flow rate (ν), drying time (t), and rehydration ratio (RR) for moisture removal of olive leaves. For this purpose, final moisture content (MC) and moisture loss (ML) were modeled and optimized by using soft computing methods. Pareto sets were obtained from predicted quadratic linear models using the least-squares (LS) approach. The nondominated sorting genetic algorithm-II (NSGA-II) was used for optimization. The compromise solution was obtained using the fuzzy c-means clustering algorithm (FCM) algorithm, one of the multicriteria decision-making methods. When the olive leaf is dried under optimum conditions determined by FCM (Tg = 63.84°C, v = 1.700 m/s, t = 997 s, RR = 2.21%), the experimental values for total phenolic content (TPC) and oleuropein amount were (20.07 ± 1.01) mg GAE/g dw and (7.30 ± 0.71) mg/g dw, respectively. It was found that drying olive leaves under low airflow rate and low hot air input temperature resulted in less alteration of TPC and oleuropein amount. Practical applications: After drying olive leaves under optimum conditions, high value-added compounds and phytochemicals can be obtained. A chemometric study based on soft computing approaches can be used for a drying process. Optimization of predicted fuzzy responses can be achieved in a multi-objective perspective through the nondominated sorting genetic algorithm-II (NSGA-II). Soft computing-based modeling and optimization tools can be applied to determine the optimum conditions of chemical, food, and pharmaceutical industry processes.