Background: It is vital to ensure that dental services are provided for HIV-positive (+) patients. Objectives: This study was designed to evaluate dentists' knowledge, attitude, and practice towards HIV+ patients of Shiraz, Iran. Methods: In this cross-sectional study, 120 general dentists of Shiraz were randomly selected. Dentists' knowledge and attitude about HIV oral manifestations and transmission, concerns and approach to HIV+ patients, and infection control in practice were assessed using a questionnaire translated in a backward-forward method. The dentists' real practice was assessed by sending simulated HIV+ patients to their practice two months later. The results were analyzed using the chi-square test and the spearman correlation. Results: The response rate was 85.8%, and 71.8% of the participants were male. The average age and work experience of the participants were 42 and 14 years, respectively. Dentists' knowledge about HIV oral manifestations and body fluids, which could transmit HIV, was 14% - 59% and 31% - 97%, respectively. Concern about the possibility of being infected during the treatment of HIV+ patients was the most important reason for the unwillingness to accept these patients. The percentages of dentists who claimed would accept HIV+ patients without hesitation, accept with hesitation if the patient insisted, refer, or reject immediately were 29, 31, 30, and 10, respectively. However, in reality, the observed percentages were 17.5, 0, 65, and 17.5, respectively. Conclusions: Dentists' knowledge and attitude towards HIV+ patients and the acceptance of these patients were not desirable. Moreover, there was no significant correlation between their knowledge and attitude with their real practice.