This study aimed to investigate the caries experience and its impact on preschool children’s quality of life and the associations between these outcomes and underlying determinants. A survey was conducted on 5- to 6-year-old children (503 in all) in Bangkok who were orally examined and interviewed on their oral health–related quality of life (OHRQoL). In addition, behavioral questionnaires were sent to parents. Associations between determinants and oral health outcomes were tested through logistic regression. It was found that 28% of children experienced high-level impacts on quality of life, mostly dental pain (58.3%) and eating difficulties (45.9%). Children of low socioeconomic status were more likely to have a high level of dental caries and subsequent OHRQoL impact. Oral status was related to oral behaviors and OHRQoL. Social disparities in preschool children’s OHRQoL were identified.