Impairing irritability is highly prevalent in children with attention deficit/hyperactivity disorder (ADHD), although manifestations of irritability are not necessarily present in all settings (home, school, with peers). At the moment, little is known about the relative prevalence, stability, and etiologies of contextual versus cross-situational manifestations of irritability in ADHD. In this study, levels of dysfunctional parenting practices and sleep problems were compared in irritable versus nonirritable children with ADHD, in cases of family-restricted versus cross-situational irritability, and examined as predictors of irritability levels over a one-year interval. Stability of irritability manifestations over time was investigated, and prevalence of cross-situational disruptive mood dysregulation disorder (DMDD) versus 'family-restricted' DMDD was compared. One hundred and seventy children with ADHD (age 6-11) were examined. Parents completed a semi-structured interview and questionnaire to assess irritability, and parent-report questionnaires were used to evaluate parenting practices and sleep problems. Questionnaires were completed for a second time after a one-year interval. Parenting practices were more dysfunctional in the irritable group compared to the nonirritable group, while sleep problems did not differ between these two groups. Levels of parenting practices and sleep problems did not predict later irritability after correction for multiple comparison nor did they differ between the family-restricted and cross-situational irritable groups. Finally, family-restricted irritability was as prevalent and as stable over time as cross-situational irritability and family-restricted DMDD as prevalent as cross-situational DMDD. Factors associated with contextual versus cross-situational manifestations of irritability in ADHD remain elusive. More subtle measures of parenting practices should be considered, including psychological control or accommodation, and other constructs such as social inhibition. Despite not being captured by current nosography, severe forms of family-restricted irritability may be as prevalent as severe forms of cross-situational irritability. © 2020 Association for Child and Adolescent Mental Health.