The importance of oxygen in wound healing and the negative effects of cigarette smoking have been demonstrated in various studies. In this study, our aim was to investigate the effect of hyperbaric oxygen (HBO2) treatment on wound healing in nicotinized and nonnicotinized rats. The study was conducted on 32 Sprague Dawley rats. The rats were divided into four groups, with eight rats in each: group 1, nonnicotinized rats; group 2, nonnicotinized rats treated with HBO2; group 3, nicotinized rats; and group 4, nicotinized rats treated with HBO2. To prepare the nicotinized groups, the rats were given nicotine for 28 days. At the end of day 28, standard, deep, second-degree to third-degree burns were created on the rats. The HBO2-treated groups underwent HBO2 treatment once a day for 7 days after the creation of the burn damage. All rats were killed 21 days after injury, and the burns were subjected to macroscopic, histopathological, and microbiological evaluation. During this evaluation, the smallest necrotic areas and the lowest rate of fibrosis were observed in group 2. The largest necrotic areas and the highest inflammation and fibrosis rates were observed in the nicotine-treated group 3. When the nicotinized and nonnicotinized groups were compared separately, there was a significant difference in favor of the groups treated with HBO2. Bacterial growth was the highest in the nicotinized group 3, whereas no statistically significant difference was observed among the other groups. We conclude that HBO treatment accelerates the recovery of burn wounds and provides more effective healing by reducing the development of scars both in nicotinized and nonnicotinized rats.