Aims: In this study, the effects of supplementary feeding during gestation and lactation period on birth and weaning weights of kids and milk yield of dams in Kilis goats were investigated. Methods and Results: In the study, experimental goats were divided into three groups as control group, short-term feeding (STF) group and longterm feeding (LTF) group. The control group was kept under breeder's management conditions. Supplementary feed of 750 g/head/day were given to the goats from the last 20 days of gestation to 90th days after birth in the STF group, and from last 40 days of gestation to the end of lactation in LTF group. At the end of the experiment, the highest lactation period was 220.2 days in the LTF group, followed by STF and control groups (P <0.05). Likewise, in the LTF and STF groups, the lactation milk yield, which was determined as 466.2 and 426.3 liters respectively, was higher than the control group (316.4 liters) (P <0.05). Conclusions: It was concluded that supplementary feeding during gestation and lactation periods caused an increase in milk yield and lactation length of Kilis goats. Significance and Impact of the Study: At the end of study, it can be stated that if supplementary feeding is made during gestation or lactation, milk yield characteristics of Kilis goats will be improved. Suckling period for the goats is the period when pasture conditions are good. For this reason, even in the goats managed only in the pasture, milk yield of mothers is sufficient for multiple born kids.