Early weaning results in intestinal dysfunction in piglets while sulfur amino acids (SAA) are involved in improving intestinal functions. We tested a hypothesis that dietary supplementation with SAA can improve intestinal functions of weaning piglets and analyzed the effects of different dietary SAA levels on intestinal functions. A total of 80 piglets (Duroc × Landrace × Yorkshire) were weaned at 21 d of age and randomly assigned to one of five diets that contained 0.53, 0.63, 0.74, 0.85, or 0.96% SAA, which corresponded to 70, 85, 100, 115 or, 130% of the SAA:Lys ratio recommended by the NRC (2012). The 14-d feeding experiment involved 16 pens per diet, and one piglet per pen. Eight randomly selected piglets from each treatment were euthanized for tissue sampling on d 7 and 14 post-weaning. Supplementation with SAA led to a rise over time in G:F (linear, P = 0.001; quadratic, P = 0.001). Between d 0 and 14 of treatment, the jejunal crypt depth decreased (linear, P = 0.018; quadratic, P = 0.015) while that of the duodenal villus (linear, P = 0.049) and ileal villus width (linear, P = 0.029; quadratic, P = 0.034) increased. The activities of jejunal alkaline phosphatase were quadratically increased (P = 0.040) from d 0 to 14 due to dietary SAA. Dietary SAA also elevated the activities of jejunal lactase (linear, P = 0.003; quadratic, P = 0.004), jejunal sucrase (linear, P = 0.032; quadratic, P = 0.027), and jejunal contents of glutathione from d 0 to 7, as well as the activity of jejunal maltase (linear, P = 0.014; quadratic, P = 0.001) between d 0 and 14. During the first wk, dietary SAA linearly increased the amounts of I-FABP (P = 0.048) and SGLT-1 (P = 0.021), and linearly decreased the amount of GLUT2 (P = 0.029) proteins in the jejunum. The abundance of jejunal I-FABP (P = 0.044) and PEPT1 (P = 0.049) protein linearly increased from d 0 to 14 in response to this supplementation. These findings indicate that there is a dose-dependent response to dietary SAA on feed efficiency and intestinal parameters of weanling pigs.