A total of 1296 pigs (Large White × Landrace) were selected at 16 weeks of age and used to investigate the effects of supplemental dietary fat concentration on finisher growth performance. Pigs were selected at an average weight of 64.0 kg and allocated to a 2 × 6 factorial experiment with the respective factors being sex (entire male and female) and supplemental dietary fat concentration (1, 2, 3, 4, 5 and 6% added tallow). All pigs were offered the respective diets ad libitum from 16 weeks of age through to slaughter at 21 weeks of age. Over the entire 5-week period, feed : gain ratio improved linearly with increasing supplemental fat concentration (P < 0.001), reducing from 2.60 to 2.44 with an increase in dietary fat concentration from 1 to 6%. Improvements in daily gain were more pronounced during the initial 14-day feeding period, increasing linearly (P = 0.002) from 844 g/day (1% fat) to 942 g/day (6% fat). Carcass weight also improved linearly (P = 0.009), increasing from 74.1 kg (1% fat) to 75.8 kg (6% fat). A greater response was observed in the males, with an increase in supplemental fat concentration from 1 to 6% improving daily gain by 7%, reducing the feed: gain ratio from 2.55 to 2.31 and improving profit per pig by AU$4.17. The effects of increasing dietary fat concentration were more moderate in females, with potential profit increases of AU$1.47. These results suggest that adding up to 6% supplemental fat to finisher diets improves profit under Australian conditions, with the benefits greater in male than female pigs. The economic impact of such a feeding strategy will, however, depend on the pig’s genetic propensity for fat deposition and the pricing system in which the pigs are sold.