Sorghum dried distillers’ grain with soluble (S-DDGS) has not been utilized as supplement in lamb growing and finishing diets under grazing conditions in summer. The hypothesis was that the performance of post-weaning lambs grazing Paspalum notatum (PN) INIA Sepé supplemented with an energy-protein diet (whole sorghum grain [SG], and soybean meal [SM]) is not reduced by the inclusion of 40% S-DDGS. During 82 days, in summer, 42 Merino Dohne male lambs (130 ± 7.6 days of age, 32 ± 2.4 kg of body weight [BW], and 2.2 ± 0.2 body condition score [BCS]) were evaluated, in a completely random experimental design with three treatments and two replicates each (n = 14 each one). All lambs grazed PN INIA Sepé and in two treatments they were daily supplemented (1.7% BW) with different components. The treatments were: PN (control group, no supplementation), SGSM (70% SG, 30% SM) and DDGS (45% SG, 40% S-DDGS, and 15% SM). Supplemented lambs had higher (P<0.0001) body weight gain (BWG), final BW and wool growth (140 and 126 g/a/d, 43.5 and 42.4 kg; 1814 and 1892 µg/cm2/d for DDGS and SGSM, respectively) than control lambs (40 g/a/d; 35.5 kg; 1353 µg/cm2/d) (P<0.0001), without differences between supplemented groups. Gastrointestinal nematodes infestation (GIN) was affected by the treatments on day 69, where supplemented animals showed lower infestation levels than control lambs (P=0.0024). The inclusion of S-DDGS in the supplement did not reduce the productive performance of the lambs when the concentration of crude protein and energy remained constant.