β-Carotene, a natural additive that is often used for food coloring, is converted into vitamin A in the body and it removes reactive oxygen species. β-Carotene accumulates in the liver and adipose tissue, where it can induce adverse effects if present in excess. In this study, we determined whether β-carotene supplementation of a high-fat/high-sucrose diet enhances liver inflammation and fibrosis in Mongolian gerbils, which accumulate β-carotene in the liver. Ten-week-old male Mongolian gerbils were divided into four groups and fed either a normal diet, a high-fat/high-sucrose diet, a high-fat/high-sucrose diet supplemented with a low dose of β-carotene (0.001%), or a high-fat/high-sucrose diet supplemented with a high dose of β-carotene (0.004%). An oral glucose tolerance testing was performed after 12 weeks, and non-fasted serum and tissue samples were collected after 13 weeks of diet feeding. The high dose of β-carotene increased triglycerides and total cholesterol serum concentrations. Intake of a high-fat/high-sucrose diet with a high dose of β-carotene increased the β-carotene content, volume occupied by fat droplets, degree of fibrosis, and protein levels of matrix metalloprotease-9 (a marker of inflammation in steatohepatitis) in the liver. These data suggest that the intake of excessive amounts of β-carotene for 13 weeks exacerbates high-fat/high-sucrose diet-inducible inflammation and fibrosis in the liver in Mongolian gerbils. This model is suitable for studying the mechanism of β-carotene-induced liver injury, including liver fibrosis.