The primary objective of this study was to determine whether there was a significant difference in the degree of improvement after orthodontic treatment between a sample of First Nations orthodontic patients and a control sample of non-First Nations orthodontic patients. The secondary objective was to determine whether there was a difference in the severity of malocclusions being treated in a sample of the First Nations patients compared with a control sample of the non-First Nations patients. Several factors that might affect treatment outcome, such as missed appointments, treatment duration, oral hygiene, extractions, dental classification, and geographic location, were also studied. A sample of 60 First Nations patients and a control group of 60 non-First Nations patients between the 11 and 18 years of age who had been treated with full fixed orthodontic appliances were evaluated. The weighted peer assessment rating (PAR) index was applied to pretreatment and posttreatment study models to address the study's main objectives. The results showed that the First Nations group had greater PAR scores pretreatment than did the controls, and their weighted PAR scores improved more with treatment. Posttreatment PAR scores were similar between the 2 groups. In addition to First Nations status, only extractions and geographic location affected PAR improvement scores.