The aim of this study is to obtain oleuropein, which is the main phenolic compound content of olive leaf by soxhlet extraction. Oleuropein has been known in the health field for a long time and is found in high rates in our country. In this context, the effect of various solvent types (ethanol, methanol, acetonitrile and water), extraction time (4 cycles, 4 hours, 8 hours), particle size (250-500 µm and 900-2000 µm) and the pre-treatment applied to the olive leaf on the yield of oleuropein was investigated. The amount of oleuropein in the liquid product was determined using a High Performance Liquid Chromatogram (HPLC). When the grain size of the raw material to be used in extraction was reduced, higher oleuropein was obtained. The use of solvents in an aqueous form resulted in a higher amount of oleuropein compared to pure solvents. Increasing the extraction time caused a significant increase in the amount of oleuropein. On the contrary, it was observed that the pretreatment applied to olive leaves caused a decrease in the yield of oleuropein. As a result of these findings, the highest oleuropein amount and extraction efficiency were obtained after 8 hours of extraction period by using olive leaf with 250-500 μm grain size and 80% methanol solution as the solvent. The highest oleuropein amount was found to be 13.35 oleuropein mg/g dry leaves and the highest extraction efficiency under these conditions was found to be 36 %.