Objectives: To assess the changes in the oral health-related quality of life (OHRQoL) of 221 preschool children who presented to the emergency department with the consequences of untreated dental caries requiring dental extractions under general anaesthesia (DEGA). Methods: Two hundred and twenty-one healthy preschool children, who required emergency DEGA, were recruited over a period of 12 months. The same parent or caregiver completed the Early Childhood Oral Health Impact Scale (ECOHIS) questionnaire; both, prior to the DEGA and at the 2-week post-treatment visit. Data were analysed using repeated anova with adjustments for multiple comparisons using the Bonferroni tests with the significance level set at 5%. Results: One hundred and twenty-six participants, with a mean age of 4.02 and a mean dmft score of 8.27 (SD = 4.13), completed the 2-week post-treatment questionnaires. The overall ECOHIS, CIS, and FIS scores decreased significantly (P < 0.001) after emergency DEGA, demonstrating large effect sizes. The biggest decrease in prevalence after emergency DEGA was observed for the items of pain in teeth, trouble sleeping, being irritated or frustrated, difficulty drinking food, and parents being upset. Conclusions: The OHRQoL of preschool children, who presented to the emergency department with the consequences of untreated dental caries, was significantly improved following emergency DEGA.