Essential oil (EO) and protected sodium butyrate (PSB) are potential alternatives to antibiotics in broiler diets. This study compared the effects of EO and a combination of EO and PSB on growth performance, carcass traits, digestive organ characteristics, intestinal morphology, and mortality in broiler chickens. A total of 2 400 one-day-old male broilers were randomly assigned to four dietary treatments: a control diet (CO), 0.1 g/kg enramycin (AB), 1 g/kg EO, and 0.25 g/kg EO + 0.75 g/kg PSB (ES), each with six replicates. One bird per pen was selected on days 21 and 35 to evaluate carcass traits and digestive tract length and weight. Growth performance variables and carcass traits did not differ between treatments (P > 0.05). However, mortality was higher in the AB group at several time points (P < 0.05). The ES treatment increased crop, gizzard, and liver weights on day 21 (P < 0.05) and gizzard weight on day 35, while EO reduced caecum weight on day 35. ES also increased the lengths of the small intestine and jejunum on day 21 (P < 0.05). On day 21, AB, EO, and ES increased colon length compared to CO (P < 0.05). Jejunal morphology showed reduced crypt depth and a higher villus-to-crypt ratio in all treatment groups (P < 0.05). On day 35, ES resulted in the shortest ileal villi and the greatest villus width, whereas EO reduced villus surface area (P < 0.05). In conclusion, dietary EO combined with PSB altered selected digestive organ traits and intestinal morphology in broiler chickens, whereas enramycin increased mortality without improving growth performance.