The impact of nano-selenium supplementation on lipid metabolism, liver enzymes, renal function, and protein levels in male lambs was investigated in this study during a 60-day period. Lambs were divided into two groups - control and experimental, which were administered nanoselenium orally at a dosage of 0.5 mg/ kg of feed once a day, daily. Each group consisted of five male lambs. According to the findings, cholesterol levels dropped significantly at days 45 (P < 0.01) and 60 (P < 0.05), whereas triglyceride levels significantly rose at days 15 and 30 (P < 0.01). Throughout the trial, the levels of uric acid and creatinine were constant. At days 15 and 60, aspartate aminotransferase (AST) levels were significantly decreased (P < 0.05), while at days 45 and 60, alkaline phosphatase (ALP) levels declined (P < 0.01 and P < 0.05, respectively). At days 15 and 30, albumin levels dropped significantly (0.05), but day 60 saw an increase in globulin levels significantly (P < 0.05). The drop in AST and ALP levels might be a sign that liver function has possibly improved. However, the drop in albumin levels and rise in globulin levels raise the possibility that taking nano-selenium supplements may affect how proteins are metabolized. The findings of this study concluded that the effects of nano-selenium supplementation on lipid metabolism, liver enzymes, renal function, and protein levels in male lambs were time-dependent. In addition to possible improvements in liver function based on decreased AST and ALP levels and changes in albumin and globulin levels, the study also noticed an initial transient increase in triglyceride levels that was followed by a decline in cholesterol levels. To determine the time-dependent changes in liver function, liver enzymes, as well as renal function in response to nano-selenium supplementation in male lambs was objective of this study.