The Genetically Improved Farmed Tilapia (GIFT, Oreochromis niloticus) strain is one of the more successfullyintroduced farmed tilapia in China because of its strong adaptability, rapid growth, high fecundity, andability to accept a broad diet. Similar to other fish and vertebrates, tilapia cannot synthesize 18-carbon polyunsaturatedfatty acids (PUFAs) and, thus, require a dietary source of n-6 series FAs (18: 2n-6 or 20: 4n-6) for normalgrowth and reproduction. Although the optimum n-6 FA dietary requirements for tilapia < 10 g have been estimatedto be 0.5%–1.0%, few studies have investigated the linoleic acid (LA) requirement for larger juvenile tilapia.Our objective was to determine the optimal dietary LA requirement for larger juvenile GIFT. A total of 630fish (mean body weight, 60.98±3.82 g) were divided randomly into seven groups with three replicates of 30 fish ineach replicate. Seven diets with a constant dietary lipid level (8%) were formulated to contain seven levels [0.07%(control group), 0.36%, 0.61%, 1.03%, 2.00%, 3.00%, and 4.15%] of LA by supplementation with corn oil andpalmitic acid to modulate FA contents. The fish were fed three times daily (8:30, 12:30, and 16:30) to apparentsatiation for 10 weeks. At the end of the feeding trial, growth performance, body composition, serum biochemicalindices, and FA composition were measured. The results showed that weight gain rate (WGR), feed efficiency rate(FER), protein efficiency rate, and protein retention rate (PRR) of GIFT increased initially and then decreased asLA level increased. A second-order regression analysis showed that the optimal LA level for the best WGR was2.49%, and that the dietary LA level for the best FER was 2.66%. Broken-line regression analyses of PRR againstdietary LA level indicated that the dietary LA level for the best PRR was 1.02%. Increasing dietary LA level contributedto increase tissue and whole-body lipid levels. Serum total cholesterol and triglyceride (TG) levels werelowest in the group fed 1.03% LA, whereas the 1.03% LA group had the highest high-density lipoprotein cholesterollevel. Low-density lipoprotein cholesterol content declined as LA increased. Broken-line regression analysesshowed that the optimum LA requirement for the minimum TG level was 1.13%. Tissues FA composition was affectedby dietary FA composition. Muscle and liver saturated fatty acid levels declined as dietary level decreased;however, muscle and liver n-6 FA levels increased and n-3 FA levels declined with the increase in LA level. Ourcomprehensive analysis of growth performance, serum biochemical indices, and FA compositio