In recent studies, it has been suggested that irisin, a myokine associated with exercise, plays a role not only in energy metabolism, but also in regulating the differentiation and specialisation of placental trophoblast cells. The aim of this study was to investigate the histological development of the interplacentomal region and the placentomal in Siirt Hair goats, and to determine the immunohistochemical expression and localisation of irisin at different stages of pregnancy. For the study, placental tissue was obtained from 18 fetuses collected from private slaughterhouses and determined to be at various stages of gestation. After routine tissue processing, haematoxylin and eosin (H&E) staining was used to examine the morphological structure and immunohistochemistry was used to evaluate irisin expression. Histological analysis shows that the placenta consists of a maternal caruncle and a fetal cotyledon. The primary villi were initially separated from the chorionic plate and transformed into secondary and tertiary villi in later stages of gestation. Irisin was detected in both maternal and fetal placental tissues, as well as in the interplacental region of goats. The strongest expression was observed in the maternal stroma during the early stages of pregnancy (p<0.05). While most differences between gestational stages were not statistically significant, these data suggest that irisin may be a regulator of early placental development and maternal–fetal relations.