Background Maternal and paternal education are associated with improved early child outcomes. However, less is known about how these relative associations compare for preschool children’s growth versus development outcomes; and across country contexts.

Methods We analysed data from 89 663 children aged 36 to 59 months in 39 low-income and middle-income countries (LMICs). We used linear regression models with country fixed effects to estimate the joint associations between maternal and paternal education and children’s growth and development outcomes. Additionally, we examined the variability in these relationships by each country and within subgroups of countries.

Results In the pooled sample, maternal and paternal education were independently associated with 0.37 (95% CI 0.33 to 0.41) and 0.20 (95% CI 0.16 to 0.24) higher height-for-age z-scores, and 0.31 (95% CI 0.29 to 0.34) and 0.16 (95% CI 0.14 to 0.18) higher Early Childhood Development Index z-scores, respectively (comparing secondary or higher to no education). Associations were stronger for maternal education than paternal education but comparable between child outcomes. In country-specific regressions, we found the most heterogeneity in the associations between maternal education and children’s growth; and between paternal education and children’s development. Subgroup analyses suggested that these associations may be systematically patterned by country-level adult illiteracy, infant mortality and food insecurity.

Conclusion Our findings highlight variability in the statistical significance and magnitude of the associations between caregivers’ education and children’s outcomes. Further research is needed to understand the sources of variation that may promote or constrain the benefits of caregivers’ education for children’s early health and development in LMICs.