<p>Using an accurate growth curve to estimate the suitable age for slaughter has many benefits for ostrich farming. This study was carried out to compare eight growth curve models for estimating body weight and monthly gain of ostriches raised in tropical conditions and then suggested the suitable slaughter age for these ostriches. Two hundred eighty-two ostriches (124 males and 158 females) were raised from birth to 12 months of age to measure individual monthly body weight, and the growth data was analyzed by R software. Eight growth functions (von Bertalanffy, Bridges, Janoschek, Gompertz, Logistic, Lopez, Richards, and Weibull) were used to create the growth curves of ostrich. The Weibull function was the best model among 8 tested models to describe the growth of both male and female ostriches, and the monthly gain (MG) reached the maximum at the 6^th month of age. The maximum average monthly gain (AMG) was obtained between the 9^th and 10^th month of age for both males and females. The best-fit model in this study (Weibull function) suggests the suitable slaughter ages were estimated from the 9^th to 10^th month of age for both male and female ostriches, with estimated body weights of 93 kg for male and 90 kg for female.</p>