Objective: This study aimed to investigate the effect of opium dependency on the healing of third-degree burns in rats. Material and Methods: Twenty-four rats were randomly divided to experimental and control groups. In the experimental group, opium was added to the drinking water for 21 days at increasing concentrations. The control group did not receive opium. To prove dependency on opium in the rats, naloxone was injected intraperitoneally. Full-thickness burn wounds were inflicted by applying an iron cuboid preheated to 94°C to the flank of all rats for 20 s. On day 14 after burn injury, full-thickness biopsies were taken. Blind histopathologic evaluation was performed to assess length and thickness of the re-epithelialization area, number of neutrophils, fibroblasts, mononuclear cells and new vessels, and percentage of tissue in repair (neutrophilic exudate, and granulation and fibrous tissue). Findings were analyzed using SPSS software. Results: The wound surface area was 95 ± 43.35 mm² in the control group and 120.4 ± 50.12 mm² in the experimental group (p = 0.224). The findings show that opium dependency has no significant effect on the healing of burn wounds in rats except for the number of monocytes on day 14 (p < 0.05). Conclusion: Morphine dependency does not seem to be as effective on third-degree burn healing.