Goat rearing is a key livelihood sector in Ethiopian agriculture, upheld in diversified agroecology and inputs, which calls for the study of innate performances description. Moreover, performance determination at age intervals has an immense role in management and genetic interference in the near future for selection and upgrading. As a result, the study aimed to evaluate the effects of agroecology, birth type and sex on the growth performance of Arsi-Bale goat-born kids under old-style supervision practices in three agro-ecologies. Live body weight data were recorded on 71 kids from the birth period until yearling age for a total of 25 days in a year. Statistical Analysis Systems version 9.4 was used to analyse the data. The average live weight at birth, three months, six months and yearling ages were 2.0, 7.6, 13.0, and 19.3 kg, respectively. As well, the average weight gain immediately after birth, three months, six months and yearling ages were 125.3, 60.4, 70.1 and 40.2 g/day, respectively. The effect of agroecology was highly significant (p≤0.01) at birth, weaning and yearling ages. Moreover, live body weight and weight gain at six months and yearling ages were higher in midland and lowland agro-ecologies. However, three-month-old weight gain was nonsignificant (p≥0.05) among the environs. Kids born single were significantly higher (p≤0.01) at birth weight but no differences (p≥0.05) were observed across the rest of the ages on birth type. An increment in live weight and daily weight gain was higher in the females when aged due to sexual characteristics differences for early maturation. Thus, the effects of agroecology and sex was higher for performance variation under prolonged thermal pressure across seasons as well as sharing of dam milk for home consumption was an added factor in the lowlands. As a result, improvement of quality and quantity feeds and shelters for day-night thermal stress effects in routine seasonal changes can lead to a reasonable advance in yield of Arsi-Bale goat’s kids. Key words: Agroecology, birth weight, body weight, daily weight gain, yearling weight