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We investigated the developmental expression and localization of <i>sf-1</i> and <i>dax-1</i> transcripts in the brain of the juvenile orange-spotted grouper in response to steroidogenic enzyme gene at various developmental ages in relation to gonadal sex differentiation. The <i>sf-1</i> transcripts were significantly higher from 110-dah (day after hatching) and gradually increased up to 150-dah. The <i>dax-1</i> mRNA, on the other hand, showed a decreased expression during this period, in contrast to <i>sf-1</i> expression. At the same time, the early brain had increased levels of steroidogenic gene (<i>star</i>). <i>sf-1</i> and <i>star</i> hybridization signals were found to be increased in the ventromedial hypothalamus at 110-dah; however, <i>dax-1</i> mRNA signals decreased in the early brain toward 150-dah. Furthermore, the exogenous estradiol upregulated <i>star</i> and <i>sf-1</i> transcripts in the early brain of the grouper. These findings suggest that <i>sf-1</i> and <i>dax-1</i> may have an antagonistic expression pattern in the early brain during gonadal sex differentiation. Increased expression of steroidogenic gene together with <i>sf-1</i> during gonadal differentiation strongly suggests that <i>sf-1</i> may play an important role in the juvenile grouper brain steroidogenesis and brain development.