In this study, extraction of essential oils from the peels of lemon (Citrus aurantifolia) was conducted and optimized. Response Surface Methodology (RSM) was adopted to optimize four process parameters including the ratio of water and lemon peel (2:1 to 4:1 mL/g), extraction time (1 to 2 h) and extraction temperature (110 to 130 °C) to achieve maximal oil yield. The results showed a ratio of 3:1 (mL/g), extraction time of 1.6 hours, a temperature of 120 ºC produced an oil yield of 2.097%. In addition, GC-MS results revealed a total of 15 identified compounds in lemon essential oil with the major compound being Limonene, accounting for 66% of total content. The study applied surface response methodology to optimize the hydrodistillation conditions for extracting lemon essential oil. Application of this computer software is particularly advantageous in reducing the experiment number while producing reliable results.