Byproduct supplementation in livestock rations is viable and can lead to increased returns to producers. Increasing the inclusion of dried distiller’s grains with solubles (DDGS) was hypothesized to increase growth performance in feedlot and growing ram lambs, while negatively affecting reproductive characteristics of ram lambs. Ethanol production in the United States provides an affordable byproduct feed for livestock, in the form of DDGS. Due to its RUP and energy content, DDGS can be readily incorporated into ruminant diets, with S concentration being the main concern for livestock health. The impacts of DDGS on feedlot lamb performance were evaluated on 240 crossbred (Suffolk × Rambouillet) lambs in a completely randomized design with a 3 x 2 factorial arrangement of treatments. Lambs were placed into 24 feedlot pens (4 pens/treatment) for a 111 d finishing study. Treatments included increasing concentration of DDGS (0, 15, or 30% DM basis) and inclusion of LAS (0 or 22.05 g/metric ton LAS) resulting in treatments of: 1) 0% DDGS without LAS (0DDGS-NL), 2) 0% DDGS with LAS (0DDGS-L), 3) 15% DDGS without LAS (15DDGS-NL), 4) 15% DDGS with LAS (15DDGS-L), 5) 30% DDGS without LAS (30DDGS-NL), and 6) 30% DDGS with LAS (30DDGS-L). The inclusion of LAS increased (P ≤ 0.02) final BW, ADG, G:F, and HCW. To evaluate the effects of DDGS on growth performance and reproductive traits in ram lambs, 112 Suffolk and Hampshire ram lambs were allocated to four treatments (n = 4 pens/treatment) in a completely random design. Basal diets were 60% corn, 25% oats, and 15% commercial market lamb pellet (CON). Treatments were (% DM basis): 15% of the ration as DDGS substituted for corn (15DDGS), 30% of the ration as DDGS substituted for corn (30DDGS) and 45% of the ration as DDGS substituted for corn (45DDGS). Rams were fed to d 112 on their respective treatment (PHASE 1), after which rams were placed on the CON ration until d 168 (PHASE 2). Many growth traits exhibited positive quadratic or cubic effects (P ≤ 0.05), indicating a possibility of both DDGS and LAS being viable supplements for sheep in growing rations.