Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)To compare the oral health-related quality of life (OHRQoL) of children (8- to 10-year-olds) and preadolescents (11- to 14-year-olds) with different oral conditions and to identify concepts associated with their perceptions of oral health (OH) and overall well being (OWB). Materials and Methods: A cross-sectional study was conducted with 264 students who were distributed into four groups: caries, with the sum of the decayed, missing and filled teeth in the primary (dmft) and permanent dentitions (DMFT) >= 1 (n = 72); malocclusion, with the Dental Aesthetic Index (DAI) >= 26 (n = 40); temporomandibular disorders (TMD) with at least one sign and one symptom of TMD (n = 89); control, with dmft/DMFT = 0, DAI < 26 and without signs and symptoms of TMD (n = 63). OHRQoL was measured using Portuguese versions of Child Perceptions Questionnaires (CPQ) for children (CPQ8-10) and preadolescents (CPQ11-14). Differences in CPQ scores and in the frequency of responses to global ratings were assessed using Kruskal-Wallis and chi-square/Fisher's exact tests. Multiple linear regression analyses were used to identify items associated with CPQ and global scores. Results: The OHRQoL of the TMD group was statistically different from controls. The malocclusion group reported more oral symptoms and social impacts compared to controls. The variables associated with CPQ scores varied according to clinical condition. Conclusions: OHRQoL was significantly different between clinical groups and controls for both age groups. However, when comparing clinical groups, TMD and caries differed only for preadolescents. The items associated with higher OHRQoL scores were mainly psychosocial for caries and TMD groups, and physical/functional and psychosocial for children and preadolescents with malocclusions, respectively.145389401State of Sao Paulo Research Foundation (FAPESP, SP, Brazil) [2008/00325-9]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)