The aim of this research was to determine the leaf water potential (LWP) of olive trees (Olea europaea L. cultivar 'Memecik') at different irrigation levels in the coastal Aegean region of Turkey in 2008. Six different irrigation-water levels were applied by drip irrigation using Class A pan evaporation technique [I-0 (k(pc):0), I-0.25 (k(pc):0.25), I-0.50 (k(pc):0.50), I-0.75 (k(pc):0.75), I-1.00 (k(pc):1.00), I-1.25 (k(pc):1.25)]. When LWP values measured on different days were evaluated statistically, a difference at the 5% significance level was observed between treatments, with LWP values increasing significantly with an increase in the amount of irrigation water applied. In treatment I-1.25, LWP values varied from -0.71 to -0.92 MPa, while in treatment I-0, which received no irrigation and depended entirely on rain, LWP values varied from -1.72 to -2.88 MPa. In addition, a decrease was observed in LWP values from the beginning to the end of the irrigation season. Finally, a significant, generally exponential relationship was found between LWP and actual evapotranspiration.