OBJECTIVE: To measure the effect of household income trajectory on oral health-related quality of life (OHRQoL) during the transition from childhood to adolescence over 10-years. METHODS: This cohort study assessed 639 children aged 1-5 years in 2010 in Santa Maria, southern Brazil. After 10 years, the same participants were re-evaluated. Familiar household income was collected in both assessments. Four groups with different income trajectories were created by cluster analysis: "stable low income", "decreasing income", "increasing income", and "stable high income". OHRQoL was measured at follow-up using the short version of CPQ11-14. Demographic, and oral health-related information were also collected. A negative binomial regression analysis with robust variance was conducted. RESULTS: A total of 351 (54.9 % of the original sample) participants with household income data at the baseline and follow-up were analyzed. Socioeconomic mobility and income remained the same for most of the participants over the 10 years. Participants belonging to the "stable high income" category presented 37 % less risk of having a worse OHRQoL than participants belonging to the "stable low income" category. Groups that experienced changes in their income trajectories did not show significant changes in OHRQoL. CONCLUSIONS: Individuals with stable high income over time were protected from having impacts on their OHRQoL. Worsening or improvement in income over time do not influence OHRQoL. CLINICAL SIGNIFICANCE: Our findings indicate that socioeconomic factors impact subjective patient outcomes, which are considered a fundamental aspect of clinical practice.