This study was carried out to investigate the relationship between irrigation water applied at different growth stages and yield/yield components of the eggplant (cultivar Pala 49) and to determine the most critical growth periods of the plant as a response to irrigation during 2016 and 2017 years under the sub humid conditions of Yalova, Turkey. Growth stages of eggplant are vegetative (V), flowering (F), yield formation (Y), and ripening (R). Experimental treatments were determined as non-irrigation (control), full irrigation (VFYR) and 14 different deficit irrigation treatments (V, F, Y, R, VF, VR, YR, FY, VY, FR, FYR, VYR, VFR, VFY). The highest seasonal evapotranspiration (average 735 mm) was obtained from the VFYR treatment. Deficit irrigation practices applied during different growth stages have different effects on yield and yield components. The highest water use efficiency (WUE) (average 6.35 kg m(-3)) was obtained from V treatment. The highest plant height (96.5 cm) and plant diameter (14.9 mm) were obtained from the VFYR treatment as average numbers of two experimental years. Since fruit length (average 22.5 cm), fruit diameter (average 63.4 mm) and maximum yield (average 4143.2 kg) were obtained from the VFYR treatment, it was concluded that this irrigation treatment would be the best choice under local conditions. Since VFY treatment which gave the best statistical results following VFYR, it may also be recommended as a good option for water short areas.