Context: Malocclusion can seriously impair quality of life and they may affect various aspects of life, including function, appearance, interpersonal relationships and even career opportunities. Objectives: To assess and determine various factors that may influence the impact of orthodontic treatment on the quality of life of adolescents. Study design: Cross sectional study in adolescents of Moradabad was conducted on 109 males and 113 females (n=222) adolescents having a fixed orthodontic appliance, aged 13 to 22 years (mean 17.5±1.5). A pre-structured questionnaire designed by Mandall et al, with nine conceptual impact sub-scales to highlight the problem faced by the patient in daily life after wearing the appliance was used to collect the data. Unpaired t-test was used to determine the statistical significance and the influence of variables were analysed using multiple linear regression analysis. Results: Factors which demonstrated high impact were oral hygiene (Mean=3.42; SD=0.78) followed by time cons - traints (Mean=3.23; SD=0.72) and physical impact (Mean=3.00; SD=0.61). Gender difference showed statistical significance in social impact (p=0.009), time constraints (p=0.001) and travel or cost implications (p=0.009). In - ternal reliability of the questionnaire ranged from low to good (Cronbach's alpha 0.29-0.81). Test-retest reliability ranged from an intra-class correlation coefficient 0.09-0.42. Conclusions: Patients who had been comprehensively informed about their treatment had greatest levels of sa - tisfaction and compliance with treatment. Younger patients showed an earlier adaptation to treatment with fixed appliances which influenced the treatment to be started at the earliest possible age.