This study was conducted to examine the effects of different treated wastewater levels on the fruit yield and quality parameters of tomato plants. The research was carried out in Bilecik ecological conditions in the 2023 growing season. The study, which was conducted in three replications in accordance with the randomized plot design, used five different dilutions (0, 25%, 50%, 75%, and 100%) of treated wastewater levels. At the end of the study, the plant's marketable fruit yield, fruit weight, fruit length, fruit firmness, pH, water soluble dry matter (WSS) and irrigation water use efficiency were analyzed. The results obtained showed that treated wastewater had positive effects on both fruit yield and quality. The highest fruit yield and IWUE values were obtained from the parcel to which 50% treated wastewater was applied (AAS50), as 67.92 t ha^-1 and 15.36 kg m^-3, respectively. The highest single fruit weight (101.35 g), fruit length (61.88 mm) and water soluble dry matter (5.43) values were obtained when 50% treated wastewater was applied, the highest fruit weight, (64.61 mm) and pH (4.57) values were obtained when 25% treated wastewater was applied and fruit firmness (1.35 kg cm^-2) was obtained from the control subject. Although treated wastewater had an encouraging effect on efficiency and quality, it was determined that it had negative effects on both efficiency and quality when the wastewater level exceeded 75%.