The determination of the maximum slaughter weight which will not cause a decrease in carcass quality is a very important issue to ensure optimal utilization of the meat production potential of lambs. To determine that, the slaughtering and carcass characteristics of thin-tailed Kivircik (n = 60) and fat-tailed Kangal Akkaraman (n = 59) lambs slaughtered at 20, 28, 36, 44, and 52 kg were investigated in the current study. The results of the present study indicate that the carcass quality was significantly affected by the slaughter weight (SW) in Kivircik and Kangal Akkaraman lambs. In Kivircik breed, the differences between SW-44 and SW-52 groups were not significant in terms of percentages of the valuable carcass parts (anterior rib and loin rib percentages), muscle, intermuscular fat, subcutaneous fat, and total fat proportions and muscle / fat ratio. On the other hand, when the allometric development of adipose tissue is considered, positive allometry was determined in the 52 kg SW group. Therefore, when the balance between the maximization of meat production and the production of lean meat suitable for the consumer's preferences is targeted, it is suggested that the Kivircik lambs would be fattened up to 44 kg. In Kangal Akkaraman lambs, the dressing percentage was similar in 36, 44 and 52 kg groups and the differences between SW-44 and SW-52 groups were not significant in terms of carcass length, chest width, hind limb length and chest roundness index. In addition, as the slaughter weight increased, the tail percentage significantly increased in Kangal Akkkaraman lambs. Also, while hind limb percentages of SW-44 and SW-52 groups were lower than the other groups, the SW-52 group had a higher total fat proportion and significantly lower muscle / fat ratio. When the allometric growth is considered, meat development slowed down after 36 kg in Kangal Akkaraman lambs, and the development of subcutaneous and intermuscular fats continued rapidly. Therefore, if we focus on producing as much saleable meat as possible from Kangal Akkaraman lambs without allowing excessive fat and tail accumulation, a slaughter weight of 44 kg can be recommended.