The aim of this study was to evaluate the general histological structure of testis in prepubertal and postpubertal stages of quails and determine the presence and location of claudin-1 and zonula occludens-1 proteins. In this study, testicular tissues obtained from 6 prepubertal and postpubertal stage quails were used. Tissue samples were fixed in 10% formaldehyde and processed for paraffin embedding. Crossman’s triple staining method was used for general his-tological evaluation. Immunohistochemistry and immunofluorescent staining were performed for the expression of claudin-1 and zonula occludens-1 proteins, respectively. It has also been concluded that the proteins of claudin-1 and zonula occludens-1 do not show immunoreactivity because an active blood–testis barrier is not formed yet in seminiferous tubule epithelium in the testis in the prepubertal period as a result of immunohistochemical and immunofluores-cence stainings but show immunoreactivity in the basal area in seminiferous epithelium with the blood–testis barrier formed in the postpubertal period. Immunoreactivity wasn’t observed in prepubertal quail’s testis. The immunoreactivity of claudin-1 has been distinguished as cyto-plasmic and membranous in Sertoli cells and spermatogonia in postpubertal quails’ testis. The immunoreactivity of zonula occludens-1 has not been observed in seminiferous tubules in prepubertal stage quail’s testis. Immunoreactivity has been observed in the basal half of seminiferous tubules in postpubertal stage quail’s testis. It has also been concluded that the proteins of claudin-1 and zonula occludens-1 do not show immunoreactivity because an active blood–testis barrier is not formed yet in seminiferous tubule epithelium in the testis in the prepubertal period as a result of immunohistochemical and immunofluorescence stainings but show immunoreactivity in the basal area in seminiferous epithelium with the blood–testis barrier formed in the postpubertal period.