Given the prevalence of malocclusions and the impact they have on oral health, patients? quality of life assessments provide useful information, not only in terms of patients? needs and expectations before treatment, but about whether or not orthodontic treatments meet them satisfactorily. The present systematic review was carried out to evaluate changes in the quality of life of adolescent patients after orthodontic treatment. An electronic search was conducted in the Pubmed, Embase, Cochrane and Scopus databases. The review followed PRISMA guidelines for systematic reviews and meta-analyses. Of the 817 studies identified in the initial search, only 10 met the inclusion criteria. In relation to the instrument used to assess oral health-related quality of life (OHRQoL), half the studies used the oral health impact profile-14 (OHIP-14) and the other half the child perceptions questionnaire (CPQ 11-14). All the studies, with the exception of Benson et al., reported a significant improvement in OHRQoL at the end of treatment. There is a positive association between OHRQoL and orthodontic treatment in adolescent patients.