Background <p>The quality of parenting can affect the developmental outcomes of young children. This study aims to investigate the associations between parenting quality and the early childhood development of children under age 3 across four major rural subpopulations in China.</p> Methods <p>Using a stratified cluster sampling method, 760 children aged 6–36 months and their primary caregivers in four rural subpopulations from four provinces and a metropolis in China were surveyed. Child development was assessed by the Third Edition of the Bayley Scales of Infant and Toddler Development. Parenting quality was measured using the Family Care Indicators. Data were analyzed using descriptive statistics, t-tests, multivariable regression analysis, and linear regression analysis.</p> Results <p>Across the four subpopulations, prevalences of delays of the sample children in four domains — cognition, language, social-emotional, and motor development are 52%, 45%, 52%, and 19%, respectively. The proportion of children with any type of delay is 82%, while over half (53%) have delays in at least two areas, and 27% have delays in three or more areas. Child’s mother as the primary caregiver, maternal education levels, and family asset values are all positively associated with the quality of parenting. Notably, low levels of parenting quality in rural China are linked to high rates of developmental delays.</p> Conclusions <p>This study demonstrates that the level of parenting quality is significantly associated with early childhood developmental outcomes. Results highlight the need for raising investments in family care to improve early childhood development in different rural subpopulations in China.</p>