AbstractObjectivesThe primary aim of this study was to evaluate if children's oral health and oral health‐related quality of life (OHRQoL) were associated with school performance. Moreover, the study aimed to examine whether school environment factors influenced this association.MethodsThis cross‐sectional study was based on a population‐based sample of 998 12‐year‐old schoolchildren from 31 public schools in Quito, Ecuador. Trained and calibrated examiners conducted clinical exams for dental caries, dental trauma and malocclusion. Furthermore, children completed the Spanish version of the Child Perception Questionnaire (CPQ_11‐14), and their parents answered questions about socio‐economic status. School coordinators provided information on the physical environment, promotion of health practices and the occurrence of negative episodes in the school. There were three outcomes: grades obtained in Spanish language and mathematics and the number of missed school days. Multilevel linear and Poisson regression models were conducted using a hierarchical approach to include the variables guided by a previously created direct acyclic graph.ResultsChildren with dental trauma and higher CPQ_11‐14 scores showed lower grades and school attendance. Schoolchildren from schools with episodes of vandalism had more school days missed.ConclusionThe school performance of 12‐year‐old children is affected by dental trauma and by a worse OHRQoL, as well as a negative school environment. Therefore, supportive environments and promoting health measures in schools could overcome this worse academic performance in children with oral health problems.