Naringin is an important flavonoid found in the fruit or peels of fruit from species of the Rutaceae family, such as grapefruit. The aim of this study was to investigate the effects of in ovo naringin injection on hatchability, hatchling weight, and hatchling length. A total of 180 fertilised Ross 308 broiler eggs were purchased from broiler flocks and randomly assigned to control (no in ovo injection), negative control (injection of 0.1 mL deionised water), and naringin (injection of 15 mg naringin in 0.1 mL deionised water) treatment groups. The eggs were incubated at 37.5 °C and 56% relative humidity and in ovo injections were made on the 18th day of incubation. Data were analysed using SPSS version 13.0, with the chi-square test used to determine the effects on hatchability, and hatchling weight and length compared using analysis of variance. The hatchability rates of the eggs in the control, negative control, and naringin treatment groups were 83.3%, 80%, and 88.3%, respectively, indicating that 15 mg naringin provided a 6% increase in hatchability. Hatchling weights were 46.26 g, 46.83 g, and 46.56 g, and hatchling lengths were 16.95 cm, 17.17 cm, and 17.28 cm, in the control, negative control, and naringin groups, respectively. In ovo injection with naringin insignificantly decreased hatchling weight, while significantly increasing hatchling length and insignificantly increasing hatchability compared to the control group. Additional research is needed to determine the most effective naringin level to obtain optimum results from in ovo injection during the incubation process.