This study was conducted to evaluate the effect of three concentrations of the Moringa oleifera seed powder as a feed supplement on the productive performance and egg quality traits of laying Japanese quail (Coturnix japonica) exposed to heat stress. The expression patterns of the genes estrogen receptors (ESR2), follicle-stimulating hormone receptor (FSHR), prolactin receptor (PRLR), and steroidogenic acute regulatory protein (STAR) were estimated in ovaries, using a quantitative real-time polymerase chain reaction. A total of 200 laying quail aged seven weeks were randomly allocated to the following four experimental groups—the control (CNT), T1, T2, and T3 groups; each group comprised 50 quail females with 5 replicates (10 per group). The CNT group was fed a basal diet, whereas the T1, T2, and T3 groups were fed the basal diet supplemented with 0.1%, 0.2%, and 0.3% M. oleifera seed powder, respectively. The results revealed that the T3 group showed the highest hen-day egg production (%) as well as the highest egg yolk index. Feed intake and feed conversion ratio improved significantly (p < 0.05) with increased concentrations of the M. oleifera seed powder supplementation. Furthermore, the mRNA expressions of ESR2, FSHR, and STAR increased significantly in the T3 group, compared to those in the CNT group. Alterations in ovarian gene expressions corresponded to the reproductive patterns of the treated Japanese quail. Thus, it was concluded that the supplementation of the Japanese quail feed with 0.3% M. oleifera seed powder during the laying period might enhance resistance to heat stress and consequently improve egg productivity