An imbalance in the production and detoxification of reactive oxygen species and other oxidants can disrupt all types of cellular compounds, and lead to a state of oxidative stress. Preventing this state is essential to improve growth and health in animal production. Therefore, the aim of this work was to assess if the dietary supplementation of curcumin could improve the antioxidant status and intestine structure and functionality of gilthead seabream postlarvae, with the global objective of improving fish growth performance and robustness. Two experimental diets supplemented with different doses of curcumin (LOW and HIGH diets), and a commercial diet were fed to quadruplicate groups of postlarvae, for 20 days. At the end of the feeding trial fish fed the supplemented diets significantly improved their antioxidant status compared to CTRL fed fish. LOW and HIGH fed fish presented lower protein oxidative damage (P < 0.05) and higher total antioxidant capacity (P < 0.05). Moreover, postlarvae fed curcumin supplemented diets also presented an upregulation of nuclear factor erythroid 2 – related factor 2 (nrf2) and glutathione-disulfide reductase (gr) in HIGH (P < 0.05) and heat shock protein 70 (hsp70) in LOW treatments (P < 0.05). No differences were observed in growth performance, intestine morphometry, and digestive enzymes activities among treatments (P > 0.05). In conclusion, dietary curcumin supplementation was able to enhance gilthead seabream postlarvae robustness through a modulation of the oxidative status, increasing total antioxidant capacity and decreasing protein oxidative damage. This data provide evidence that curcumin can be a suitable feed additive to promote heath status and robustness of fish at early stages of development, therefore contributing for the development and sustainability of marine fish hatchery production.