This study aimed to evaluate the psychometric properties of the Brazilian version of the Early Childhood Oral Health Impact Scale (ECOHIS). A total of 247 children aged 2 to 5 years and their parents/guardians participated in this study. A clinical oral examination was performed and the parents/guardians completed the ECOHIS questionnaire. Within a period of four-weeks, 20% of the participants repeated the ECOHIS questionnaire. Construct validity was determined using Spearman's rank correlation. Discriminant validity, internal consistency and test-retest reliability were also evaluated. The children were divided into 2 groups: group 1 (with dental caries) and group 2 (caries-free). Children with caries showed higher mean ECOHIS scores than the caries-free children. The child impact section (p < 0.01), family impact section (p < 0.01) and total ECOHIS scores (p < 0.01) were significantly correlated with tooth decay. Cronbach's alpha coefficients demonstrated satisfactory internal consistency. The Brazilian version of the ECOHIS is a valid instrument for assessing oral health-related quality of life in preschool children with Brazilian Portuguese-speaking primary caregivers.