Postharvest losses of tomatoes have been estimated to be more than 40%. Drying tomatoes using the appropriate dryer and condition to the optimum storage moisture content minimizes the postharvest loss. It has been reported that drying tomatoes using an oven dryer increases the drying rate and minimizes the adverse effects of unpredictable conditions during the drying stage. However, an Oven dryer is one of the promising and sustainable alternatives for the drying of tomatoes. It has negative quality effects because of a longer drying time and high energy consumption. The main objective of this study was to study the effect of ethyl oleate pretreatment on oven drying tomatoes. Chemical pretreatment like ethyl oleate can accelerate the drying tomatoes by dipping, resulting in a break-down of the waxy cuticular surface of the tomato which leads to reducing the resistance to moisture content without affecting the flavor of the final product. This study investigates the effect of ethyl oleate pretreatment on oven drying characteristics and quality of tomatoes. An oven dryer with a temperature of 50℃, 60℃, and 70℃ was used. The process used 2%, 4%, and 6% concentrations of ethyl oleate, and dipping times of 5, 10 and15 minutes. The performance was tested using a sample load of 600gm of tomatoes. The experimental data were fitted to ten different thin-layer drying models and the goodness of fit for each model was evaluated using R 2 , sum square error, and root mean square error. The modified page I model gave a better prediction of tomatoes drying in an oven dryer. Response Surface Methodology was used to optimize drying parameters such as temperature (50-70℃), dipping time (5-15 min), and ethyl oleate concentration (2-6 %v/v). An optimum drying rate of 228.452gm/hr was obtained at dipping time 10.19 min, ethyl oleate concentration 4.14%v/v, and drying temperature of 69.92 ℃. Meanwhile, a maximum drying rate of 228gm/hr was obtained from the experimental result, which shows the reliability of the predicted quadratic model. The study clearly showed that tomatoes drying in the pretreatment of ethyl oleate in an oven dryer will help growers to reduce the drying time, protect from contamination, and ultimately gives more quality dried products and reduce postharvest loss of tomatoes. Key words: Postharvest loss, Drying, Tomatoes, Ethyl oleate, Oven dryer, drying models