Background: One of vitamin A metabolites is Retinoic Acid (RA). Its signaling pathway during embryonic development regulates formation of germ layers, neurogenesis, body axis establishment and morphogenesis of the optic cup, lung, and pancreas. Its function during embryonic and post hatching growth is achieved by activating gene transcription through interactions with its receptors. Citral is a major component of essential oils extracted from several herbs. It blocks endogenous RA signaling pathway by inhibiting oxidation of retinal to RA. Aim of the work: The present work aimed to investigate the effects of exogenous RA and citral on morphdevelopmental abnormalities in ovo in the Japanese quail, Coturnix coturnix japonica, across early and late developmental stages. Methods: 445 fertilized eggs of the Japanese quail were divided into control and three groups of DMSO, RA, and citral injected before incubation and three other groups injected on the eighth day of incubation. Embryos at 7, 9, 13 days, and hatching day were collected and examined for morphology & mortality. Morphometric measurements were carried out and statistically analyzed on hatching day. Results: Both RA or citral treatments resulted in several abnormalities including anencephaly (absence of skull), anophthalmia and microphthalmia, scoliosis, wry neck, hernia, absence of feathers, and deformed limbs. RA group exhibits the highest mortality rate in case of injection before incubation. Injection on the eighth day results in the highest mortality rate in citral group. Weight, crown-rump length, head length, head circumference and head height in all groups are compared with control. Conclusion: This research shows that exogenous RA or citral treatment, affects the level of endogenous RA, and induces teratogenic effects in quail development leading to several malformations. Embryonic response to RA is highly sensitive and depends on developmental stage. Also, RA level needed for healthy embryonic growth is disturbed by citral. Embryos were more sensitive in the early embryonic stages, with mortality rate, while more resistant and survived more at late developmental stages with malformations.