We evaluated plant growth, fruit and oil characteristics of olive (Olea europaea L. cv. 'Gemlik') grown on different fertilization and irrigation treatments. Irrigation regimes included rainfed-control (T-0), two treatments with 50% (T-50) of the full irrigation treatment (T-100) which received 100% class-A pan evaporation. Four fertilization treatments included unfertilized-control (F-0), traditional fertilization (F-1) and application of P and K during different growing stages (F-2-F-3). Experiments were conducted in each of three years considered as repeated units in a repeated measurement design. Fruit and total oil yields of olive increased about three times in highest irrigation and fertilization combination compared to rainfed and unfertilized treatments. The fruit and oil yield increased from 11.46 and 2.78 kg/tree (T0F0) to 30.07 and 7.12 kg/tree (T100F3), respectively. Mean fruit weight (from 2.87 to up to 4.24 g) and pulp stone ratio (from 3.68 to up to 5.60) also increased with additional water as P and K applied during flowering and endocarp hardening stages, respectively. Fertilization treatments had little effect on fatty acid compositions while additional irrigation resulted in increased palmitic and linoleic acid and decreased oleic acid content. Monounsaturated fatty acids/polyunsaturated fatty acids ratio was also decreased with irrigation supplements.