Objective: The current study introduces the Parental Emotional Response to Children Index (PERCI), a new questionnaire specifically designed to measure parents’ emotional response to ADHD and related behaviors (delay discounting and delay aversion). Method: The PERCI was completed by parents of 6- to 14-year-old children with (n = 126) and without (n = 160) ADHD. Results: Factor analysis confirmed five separate subscales with acceptable psychometric properties. Parents of children with ADHD reported a stronger emotional response to ADHD behaviors than parents of typically developing children and inattention symptoms evoked the strongest emotional response in parents regardless of child diagnostic status. Conclusion: Parents’ emotional responses appear to be differentiated in terms of specific ADHD-related triggers mapping onto the different domains of ADHD and delay-related responses. Further research is required to understand changes in parental emotional responses over time and their impact on children’s developmental trajectories.