We aimed to identify positive parenting practices that set children on differential weight-trajectories. Parenting practices studied were cognitively stimulating activities, limit-setting, disciplinary practices, and parent warmth. Data from two U.S. national longitudinal data sets and linear and logistic regression were used to examine association of initial parenting practices with subsequent change in body mass index (BMI) Z-score and being overweight, stratified by income and gender. Lower change in BMI Z-score and lower likelihood of being or becoming overweight occurred among girls if parents engaged in cognitively stimulating activities or set bedtime; among low-income girls if parents helped with art and set bedtime; among high-income girls if they participated in dance or music, parents talked about nature or visited a museum or library, or parents had rules about number of hours for watching television; among low-income boys if they participated in dance or parents built something with them or set bedtime; and among high-income boys if they participated in dance or music. Greater expression of warmth was associated with lower change in BMI Z-score. Parenting practices facilitating cognitive stimulation, setting limits, and expressing warmth are associated with lower likelihood of being or becoming overweight and can be promoted by healthcare professionals.