In this cross-sectional, community-based study among a multi-ethnic sample of preschool-age children in North Carolina, United States, we sought to quantify the association between guardians’ self-reported oral health and their children’s oral health and determine whether race/ethnicity and education level modify these associations. We used questionnaire (n = 7852) responses about caregivers’ and their children’s oral health and clinical examination-derived (n = 6243) early childhood caries (ECC) status defined at the ICDAS ≥ 3 caries lesion detection threshold. We used multi-level mixed-effects generalized linear models to examine the associations between the guardians’ reported oral health and their children’s reported and clinically determined oral health among the entire sample and within strata of race/ethnicity, guardians’ education, and children’s dental home. The guardians’ and their children’s reported fair/poor oral health (FPOH) were 32% and 15%, respectively, whereas 54% of the children had ECC and 36% had unrestored disease. The guardians’ FPOH was strongly associated with their children’s FPOH (average marginal effect (AME) = +19 percentage points (p.p.); 95% CI = 17–21), and this association was most pronounced among Hispanics, lower-educated guardians, and children without a dental home. Similar patterns, but smaller-in-magnitude associations, were found for the guardians’ FPOH and their children’s clinically determined ECC (AME = +9 p.p.; 95% CI = 6–12) and unrestored disease (AME = +7 p.p.; 95% CI = 4–9). The study’s findings support a strong association between guardians’ and their children’s reported and clinically determined oral health and implicate ethnicity, education, and having a dental home as factors possibly modifying the magnitude of these associations.