This study describes the effects of mechanical harvesting and irrigation on quality in ‘Arbequina’ olive oil (Olea europaea L.). Irrigation treatments included a control, deficit irrigation (DI) during pit hardening, and subsurface deficit irrigation (SDI). Results showed that mechanical harvesting damaged the olives and reduced olive oil quality by increasing free fatty acids (FFAs) and peroxide value, and by decreasing fruitiness, stability, bitterness, and pungency. DI resulted in increased fruit dry weight and oil content, which could be explained by their reduced crop load (9.3% of crop reduction for DI and 23.9% for SDI). DI did not affect olive oil characteristics, whereas SDI increased stability, fruitiness, and bitterness, and decreased polyunsaturated fatty acid (PUFAs). In conclusion, mechanical harvesting tended to damage the fruit, resulting in lower quality olive oil, the DI strategy neither affected fruit nor olive oil characteristics, whereas the SDI strategy positively affected oil quality when greater water restrictions were applied.