Purpose <p>This cross-sectional study investigated the impact of pulp involvement on schoolchildren’s Oral health-related quality of life (OHRQoL).</p> Methods <p>Schoolchildren aged 5, 8 and 12 from 26 schools of Petropolis, Brazil, were examined. Dental caries was evaluated through dmf-t/DMF-T index and pulp involvement through pufa/PUFA index. Three groups were defined: caries-free (dmf-t/DMF-T = 0), caries without pulp involvement (dmf-t/DMF-T ≥ 1, pufa/PUFA = 0), and caries with pulp involvement (dmf-t/DMF-T ≥ 1, pufa/PUFA ≥ 1). A questionnaire with socioeconomic characteristics, C-OIDP instrument and a toothache question was sent to guardians. The impact on OHRQoL was analysed as categorical and numerical variables. Poisson regression was used for the categorical, and negative binomial regression for the numerical variable (significance <i>p</i> &lt; 0.05).</p> Results <p>In 5-year-olds, pulp involvement was associated with a 2.08 times higher prevalence of impact on OHRQoL (95% CI 1.12–3.86) and a 2.41-point increase in the C-OIDP score (95% CI 1.04–5.59), compared to caries-free children. In 8-year-olds, a significant association with pulp involvement was observed only when OHRQoL was analysed as a numerical variable (RR = 2.06; 95% CI 1.23–3.43). In 12-year-olds, no significant association was found.</p> Conclusion <p>Pulp involvement negatively impacted OHRQoL. Toothache was the most significant factor related to this impact.</p>