This study investigates the impact of responsive parenting on infant development, focusing on social, emotional, communication, and cognitive skills. Mothers of infants varying in biological characteristics (term and very low birth weight [VLBW]) were randomized to a target group (n = 133) or a developmental feedback comparison group (n = 131). The target group received videotaped examples, problem-solving activities, and critiques of their own behaviors across 10 home visits. Both groups showed increased responsiveness, with greater increases in emotionally supportive behaviors for mothers of VLBW infants. Increased maternal responsiveness facilitated greater growth in infant skills, particularly in social, emotional, and cognitive domains. The study also found that responsiveness had a differential effect on infants of varying characteristics, with more pronounced benefits for VLBW infants in certain skill areas. Additionally, the intervention's effects generalized to interactions with a novel adult and independent toy play, suggesting that responsive parenting helps infants develop resources to cope with stress and novelty. The findings support the importance of responsiveness in early childhood development and highlight the need for targeted interventions to enhance parental responsiveness.This study investigates the impact of responsive parenting on infant development, focusing on social, emotional, communication, and cognitive skills. Mothers of infants varying in biological characteristics (term and very low birth weight [VLBW]) were randomized to a target group (n = 133) or a developmental feedback comparison group (n = 131). The target group received videotaped examples, problem-solving activities, and critiques of their own behaviors across 10 home visits. Both groups showed increased responsiveness, with greater increases in emotionally supportive behaviors for mothers of VLBW infants. Increased maternal responsiveness facilitated greater growth in infant skills, particularly in social, emotional, and cognitive domains. The study also found that responsiveness had a differential effect on infants of varying characteristics, with more pronounced benefits for VLBW infants in certain skill areas. Additionally, the intervention's effects generalized to interactions with a novel adult and independent toy play, suggesting that responsive parenting helps infants develop resources to cope with stress and novelty. The findings support the importance of responsiveness in early childhood development and highlight the need for targeted interventions to enhance parental responsiveness.