Preschool-age “hot” executive function capacity (i.e. reward-related effortful control) represents an early kind of self-regulation that is involved in social adjustment development as well as the development of subtypes of attention-deficit/hyperactivity disorder (ADHD). Early self-regulation development might be malleable by responsive parenting. We analyzed whether maternal responsiveness/sensitivity predicts reward-related control (RRC) development within the preschool period, and whether RRC mediates a negative link between maternal responsiveness and ADHD symptoms. A sample of 125 preschoolers and their families were seen at the ages of 4 and 5 years. Maternal responsiveness/sensitivity was assessed via home observations, RRC by neuropsychological tasks, and ADHD symptoms by a structured clinical parent interview. Maternal responsiveness/sensitivity predicted RRC development. The negative link between maternal responsiveness/sensitivity at 4 years and ADHD symptoms at 5 years was mediated by RRC performance at 5 years. Preschoolers showing ADHD symptoms combined with low RRC capacity in particular might benefit from responsive/sensitive parenting.