This cross-sectional study examined the prevalence of dental caries and associated factors among children aged 12-18 years residing in orphanages at Phnom Penh, Cambodia. The study included 187 subjects (male = 103, female = 84, mean age = 13.28 ± 1.51 years), and the data was collected by means of oral examinations, DMFT scoring, oral health questionnaires based on the KAP model, and interviews conducted in a private dental clinic supported by a non-government organization. The overall caries prevalence was found to 85.2%, and 30% of the children exhibited severe caries. The mean DMFT, DT, MT and FT scores were 3.58 ± 3.00, 2.13 ± 2.54, 0.13 ± 0.44 and 1.32 ± 1.68, respectively.The proportion of children with moderate knowledge about oral health, highly positive attitudes toward oral health, and moderate levels of oral hygiene practices were 63.6%, 69.6%, and 67.3%, respectively. Significant differences in factors related dental caries were observed among different age groups (p<0.01) and sweet intake groups (p < 0.05). Conversely, no significant associations were observed between dental caries status, and the levels of knowledge, attitudes, and practices pertaining to oral health.The results of this study suggest that targeted oral health promotion programs are necessary to prevent dental caries in this population.