The aim of this study was to assess the association between oral diseases and condition-specific oral health-related quality of life (CS-OHRQoL) as a basis for proposing OHRQoL-based goals for the population of 15-year-olds in Thailand. Oral examinations and OHRQoL interviews were conducted with 871 15-year-olds as part of the Sixth Thailand National Oral Health Survey. The severity of oral impacts was categorized using "intensity". Associations between oral diseases and CS-OHRQoL were analyzed using chi-square and logistic regression. Thirty-nine percent of 15-year-olds experienced moderate/higher levels oral impacts on quality of life. Compared to those individuals with no tooth decay, adolescents with one or four or more decaying teeth were three and seven times more likely to experience moderate/higher impacts, respectively. Adolescents with extensive gingivitis in 3 or more mouth sextants were twice as likely to experience moderate/higher CS-impacts. Based on these findings, it is proposed that goals should focus on untreated decaying teeth and extensive gingivitis. Oral health goals for 15-year-olds should include specific OHRQoL measures.