Bile acids (BAs) have been shown to exert beneficial effects on growth and metabolism in various fish species. Nevertheless, few studies have focused on the impact of ursodeoxycholic acid (UDCA). The purpose of the present study was to investigate the potential effects of dietary UDCA supplementation on growth performance and lipid metabolism in juvenile large yellow croaker (Larimichthys crocea). Four diets were formulated based on a control diet (CON), with the addition of 50 mg/kg (UL), 100 mg/kg (UM), and 500 mg/kg (UH) UDCA. A total of 400 juveniles (with an initial body weight of 15.55 ± 0.02 g) were randomly distributed into 16 tanks (1000L) with 25 juveniles per tank. Each type of experimental diet was fed to the fish in four replicates twice daily. After a 10-week feeding trial, the results demonstrated that feeding diets containing 50 and 100 mg/kg UDCA significantly improved growth performance (P < 0.05). Dietary UDCA supplementation significantly increased whole-body crude lipid content, liver, and serum total cholesterol (T-CHO) content, as well as intestinal lipase activity, while reducing liver and serum free fatty acid content (P < 0.05). To investigate the mechanisms underlying the observed growth and metabolic alterations induced by UDCA, tissue samples from the CON and the UM groups were subjected to RNA-sequencing analysis. A total of 1924, 4399, 249, and 971 differentially expressed genes (DEGs) in the liver, intestine, olfactory, and brain tissues were identified, respectively. Enrichment analysis of these DEGs suggested a high degree of pathway similarity between the liver and intestinal tissues. Specifically, the UM diet markedly upregulated genes associated with lipid synthesis and lipid transport, while concurrently downregulating those involved in fatty acid β-oxidation. Weighted gene co-expression network analysis (WGCNA) across tissues revealed a gene cluster related to cholesterol synthesis. Within this cluster, key genes such as 3-hydroxy-3-methylglutaryl-coenzyme A reductase (hmgcr) and 3-hydroxy-3-methylglutaryl-CoA synthase 1 (hmgcs1) were upregulated, implying that UDCA enhances of cholesterol synthesis. Furthermore, in vitro experiments in primary hepatocyte corroborated the role of UDCA in stimulating lipid synthesis, as evidenced by the augmented total triglyceride (TG) and T-CHO levels following UDCA incubation. This increase was paralleled by an upregulation in the expression of genes related to fatty acid and cholesterol synthesis as well as lipid transport. In summary, these results demonstrate that UDCA exerts a beneficial impact on growth performance, lipid transport, and lipid synthesis in juvenile large yellow croakers.