Background <p>Bullying poses a major risk for poor mental health. While findings from the general population highlight harmful effects of bullying, data from clinical samples with diverse diagnoses and evidence-based diagnostic methods is rare. This study aimed at exploring the association between psychopathology and active bullying involvement in child and adolescent psychotherapy outpatients.</p> Methods <p>The preregistered study (<a href="https://aspredicted.org/VYW_9TT">https://aspredicted.org/VYW_9TT</a>) included data from <i>N</i> = 719 outpatients aged 6–20 years from a German child and adolescent psychotherapy centre. Current experiences as a victim, bully-victim, or bully and distressing bullying-specific intrusions were assessed with a screening instrument. Gold-standard diagnostic assessment of psychopathology provided categorial ICD-10 diagnoses. The Strength and Difficulties Questionnaire depicted a dimensional proxy measure of psychopathology. Analyses included examining the frequencies of the bullying roles (victim, bully-victim, bully) and the occurrence of distressing bullying-specific intrusions, Pearson’s chi-square tests for gender-specific differences, binary logistic regression analyses testing the bullying roles as predictors of ICD-10 diagnoses, and multiple one-way ANOVAs examining group differences on the Strength and Difficulties Questionnaire scores between the bullying roles.</p> Results <p>29% of all outpatients reported to be actively involved in bullying (22% victims, 5% bully-victims, 2% bullies), with 32% frequently experiencing distressing bullying-specific intrusions. While victims were more likely to have mood disorders (ICD-10 F3 disorders), bully-victims were less likely to have internalising and more likely to have externalising disorders and behavioural and emotional disorders with onset usually occurring in childhood and adolescence (ICD-10 F9 disorders). Bullies were more likely to have multiple disorders but less likely to have internalising disorders. Independent from specific diagnoses, victims, bully-victims, and bullies overall reported greater emotional and behavioural difficulties than outpatients without bullying experiences.</p> Conclusions <p>Among outpatients in child and adolescent psychotherapy, bullying is linked to specific related psychological burden and role-specific psychopathology. Bullying and related psychological burden should be addressed and routinely assessed in mental health care settings. The link between bullying and psychopathology as well as specific intervention methods may be explored further in future research.</p>