Despite advances in understanding associations among attention‐deficit hyperactivity disorder (ADHD), emotion dysregulation (ED), and related outcomes, there is incongruity between ADHD‐relevant conceptualizations of ED and available measures of ED. To assess the psychometric properties of a parent‐report questionnaire of ED conceptualized as deficits in the ability to modulate the (a) speed/degree of emotion escalation; (b) expression intensity; and (c) speed/degree of de‐escalation.

Participants were 209 adolescents with ADHD (78% male; 13.5–17.8 years old [M = 15.2 SD = 0.91]). Questionnaire items were selected from parent‐report scales of ED and oppositional defiant disorder and subjected to exploratory factor analysis (EFA) and validity analyses.

The EFA revealed two factors, with speed/degree of escalation combined with intensity as factor one, and speed/degree of de‐escalation as factor two. Factor one scores were related to ADHD impulsivity symptoms but not to anxiety and depression symptoms and they remained predictors of impulsivity even in the presence of self‐report ED, evincing convergent, discriminant, and incremental validity. Factor two scores were related to anxiety and depression but not impulsivity, evincing convergent and discriminant validity.

These results inform our understanding of ADHD‐relevant ED in adolescence and offer avenues for future research in measurement development, as well as for understanding ED and ADHD‐related impairment.