Subthreshold neglect is defined as the absence of positive parenting behaviors that eventually results in delayed child development. The present study tested several competing models of maternal support and infant development in a sample of 508 mothers at high and low risk for child neglect based on their age and educational levels. Infants demonstrated significantly delayed development at both 12 and 24 months of age in social-emotional competence, the absence of social-emotional problems, cognitive development, and language development. Problems in these areas were then related to maternal social-emotional, cognitive-language, and responsive supports in a model comparison approach. Results revealed that a restricted model of subthreshold neglect fit the data best. The absence of responsive support at 8 months predicted social-emotional problems and the absence of cognitive-language support predicted language delays at 12 months. The absence of responsive support at 8 months also predicted deficiencies in social-emotional competence at 24 months. Conversely, responsive support predicted language delays at 12 months. Social-emotional, cognitive, and language development at 12 months predicted corresponding development at 24 months. The findings suggested that the effects of early subthreshold neglect were immediate, but that early-appearing problems resulting from subthreshold neglect may lead to trajectories of adverse child development over time.