The aim of this study was to determine the net requirements of calcium (Ca), phosphorus (P), magnesium (Mg) and sulfur (S) for gain of high or low residual feed intake (RFI) Dorper lambs confined in full sun or shade. Sixty-four intact male Dorper lambs with an average initial body weight (BW) of 17.8 ± 2.43 kg and an average age of 70 ± 10 days were confined for 40 days to separate them into two groups (high or low RFI). Thereafter, a group of 4 animals (2 high RFI and 2 low RFI) were slaughtered to estimate initial empty body weight (EBW) and body composition of animals slaughtered at the end of the experiment. The 60 remaining lambs were distributed in a randomized block design, with a 2 × 2×3 factorial scheme, with two feedlot environments (full sun or shade, 30 animals in each), two groups of feed efficiency (high RFI or low RFI, 30 animals in each) and different levels of concentrate (30, 45 and 60 %), with 5 repetitions in each interactive treatment. The animals from each feedlot environment and from each RFI were distributed in three dietary treatments with different levels of concentrate to have different body compositions necessary to determine their macromineral requirements. The animals were confined for 60 days until slaughter. Neither RFI nor feedlot environment affected the net macromineral requirements for gain of Dorper lambs (P > 0.05). There was a decrease in net Ca, P and S requirements as fasting BW (FBW) increased from 20 to 40 kg (P < 0.05). However, the net requirements of these macrominerals for gain increased as average daily gain (ADG) increased from 100 to 300 g/day (P < 0.05). In contrast, the net Mg requirement for gain increased as both FBW and ADG increased (P < 0.05). The results showed that there was no significant effect of RFI and shade environment on the net requirements of macrominerals for weight gain of Dorper lambs. Possible differences could be in the dietary level or in the maintenance level. Therefore, further studies are needed to assess the effect of RFI and shade environment on the mineral requirements of lambs.