An experiment was conducted to determine the standardized ileal digestibility (SID) of amino acids (AA) in distillers dried grains with solubles derived from corn (C-DDGS), sorghum (S-DDGS), and triticale (T-DDGS) fed to growing pigs. A total of 16 barrows [initial body weight (BW) = 23.1 ± 2.03 kg] surgically fitted with T-cannulas at the distal ileum were divided into four groups based on BW and assigned to a quadruplicated 4 × 2 incomplete Latin square design with four dietary treatments and two experimental periods. Three diets containing C-DDGS, S-DDGS, or T-DDGS, as well as a nitrogen-free diet, were fed in each experimental period consisting of 5 d of adaptation and 2 d of ileal digesta collection. Pigs fed S-DDGS had less (P < 0.05) SID of histidine, isoleucine, leucine, and methionine compared with those fed T-DDGS, which were less (P < 0.05) than the values observed for pigs fed C-DDGS. The SID of arginine, phenylalanine, threonine, and valine in C-DDGS were greater (P < 0.05) than in S-DDGS but were not different from those in T-DDGS. The SID of lysine in C-DDGS was greater (P < 0.05) than in S-DDGS and T-DDGS. In conclusion, AA in S-DDGS were less digestible than those in C-DDGS and T-DDGS.