Moringa oil has strong antibacterial activity against a wide range of Gram-negative and Gram-positive bacteria in addition to anti-fungal properties. This study evaluated the impact of spraying hatching eggs of Japanese quail with Moringa oil solution on embryonic development, physiological parameters, hatchability, post-hatch chick growth, and bacterial load on the surface of the eggshell. Seven hundred and fifty quail eggs were divided equally into 5 experimental groups. Eggs in the 1st group were presented as a control (untreated eggs), while, those in the 2nd group served as control but were only sprayed with an organic solvent 70% ethyl alcohol.  Eggs of the 3rd, 4th and 5th groups were sprayed with 2, 4 and 6 ml Moringa oil solution /liter, respectively. Embryo weight, body length, shank length, chick weight, chick body length, chick shank length, and hatchability tended to be significantly higher (P<0.05) in eggs treated with Moringa oil solution compared with control groups. While embryonic mortality, hatch time, egg albumen weight ratio, eggshell thickness, and egg weight loss ratio at 14 days of incubation were significantly decreased (P<0.05) in the eggs that were sprayed with the Moringa oil solution compared to control eggs. The means of RBCs, hemoglobin, PCV, total protein, albumin, globulin, T4 hormone and IgG were significantly increased (P<0.05) at 1 and 14 days of age. The white blood cell count was slightly increased in response to the Moringa oil solution. The body weight, body weight gain, and feed intake of chicks at 14 days of age recorded high significant values in response to spraying with Moringa oil solution. In contrast, the percentage of yolk residual at hatch was lower than that of the control group. Treating Moringa oil solution had a significant effect on TBC and coliforms on the eggshell surface after 24 h, 7, and 14 days of incubation compared to control groups. The number of total aerobic and anaerobic bacteria in the chicks and the total coliform bacteria count decreased. In conclusion, spraying Japanese quail eggs with a solution of Moringa oil as a natural disinfectant (pre-incubation) is a good way to improve embryonic development, hatchability, blood components, thyroid hormone T4, and immunity to hatching chicks and reduce bacterial contamination of the eggshell surface of quail eggs.