Olive trees are plants native to the Mediterranean, known for their products, olive oil, and olives. However, several by-products are discarded, such as olive leaves, which have in their composition several phenolic compounds, predominantly oleuropein, a compound beneficial to health. This work aimed to develop a DLLME (liquid-liquid dispersive micro-extraction) method for the extraction and quantification of Oleuropein in olive leaves cultivated in Delfim Moreira - MG, during their pruning period. Three cultivars were evaluated (Arbequina, Grapollo, and Koroneiki) using two drying methods (oven at 35ºC and lyophilization). An HPLC-DAD was used to validate the method and quantify Oleuropein, injecting 1 to 10 µL of extract, depending on the analyte concentration. The validated method had a detection limit of 0.1 mg.kg-1, with recoveries ranging from 101.61 to 112.56% and precision from 1.68 to 12.96%. The curve with the Oleuropein standard presents good linearity, with regression equation y = 9.4772 x - 1.3252 and R2 = 0.9986. The results show that the oven-dried cv. Arbequina is below the limit of quantification, on the other hand, the lyophilized contains 2.02 ± 0.16 mg.kg-1. For cv. Grapollo, the results were 0.50 ± 0.03 mg.kg-1 and 33.87 ± 0.48 mg.kg-1 for oven and lyophilized samples, respectively. Finally, the oven-dried cv. Koroneiki has 1.00 ± 0.10 mg.kg-1 of oleuropein, compared to 3.58 ± 0.05 mg.kg-1 for lyophilized. Thus, it can be observed that drying the samples in oven favors the degradation of the compounds of interest and that the method is suitable for quantifying Oleuropein.