This study was conducted to evaluate the effect of dietary supplementation of acetic acid at different levels on milk yield and composition. A total of eighteen Awassi ewes in the early stage of lactation were used in this study, with average body weight (37.631.84) and ages (3–4 years). Animals were allocated to three treatments; the first treatment was control fed with a basal diet without additives (T1). Acetic acid (98%) was added to the concentrate feed daily before feeding by 5 mL/ewe daily in T2 and 10 mL/ewe in T3 after dilution 1:10 with tab water. Results indicate an insignificant increase in ewes' body weight in T2 and T3, which were 40.41 and 41.11 kg compared to T1 at 37.93 kg. Actual milk yield was not affected while fat corrected milk Increased in T3 was 390 g/day compared to T2 with 323 g/day. Milk fat percentage increased (p ≤ 0.05) in T3 at 6.26% as compared to T1 and T2 at 5.65% and 5.43%, respectively, while fat yield was higher (p ≤ 0.05) in T3 at 23.85 g/day than in T2 17.58 g/day. This was reflected in increased milk energy (p ≤ 0.05) in the T3 at 953 kcal/kg compared to T2 at 858 kcal/kg. From the results, it can be concluded that acetic acid can be used as an additive to the ewes diet, and effect positively in ewes’ weight and milk fat.