The Caspian horse is one of the most important native breeds of Iran, and the most significant feature of this breed is its short wither height, which distinguishes it from other native breeds. Despite the significance of this breed’s height, comprehensive data on the phenotypic and genetic parameters of this characteristic have yet to be documented for this breed. Consequently, the principal objective of this study was to examine the genetic and phenotypic structure of the Caspian horse’s stature to enhance our comprehension of this breed’s height characteristic. The study utilized data amassed from 12 distinct provinces by the Caspian Horse Conservation Society, encompassing the details of 1,032 horses (605 males and 427 females) within the pedigree, out of which 360 horses had recorded height information, to estimate the genetic and phenotypic parameters of stature. A linear regression model incorporating an additive genetic random effect and the Bayes method was employed to estimate heritability. The findings of this research indicated that, on average, males (116.88 ± 4.74 cm) had a greater stature than females (116.55 ± 5.42 cm); however, this disparity was not statistically significant. Furthermore, the analysis of the height trend with respect to age revealed that, due to the increment in height around the age of 4 years, the optimal period for measuring the stature of Caspian horses is postulated to be subsequent to this age. The heritability estimate for the trait of height in Caspian horses was found to be substantial, quantified at 44.2% (±9.8%). The ...