The quality of interprofessional collaboration is a key determinant of the success and effectiveness of integrative care for children with multiple and complex needs. This study reports on the development and first psychometric evaluation of a questionnaire that assesses professionals' perceptions of interprofessional collaboration for child welfare-involved children with severe emotional and behavioural problems. We created the scale deductively using collaboration theory and inductively based on a large qualitative study examining interprofessional collaboration between residential care and mental health services in six European countries. Psychometric properties of the Perceptions of Interprofessional Scale for Children with Multiple and Complex Needs (PICOCC) were explored using exploratory and confirmatory factor analysis with two German samples of professionals working in child welfare and child and adolescent psychiatry (N = 360). Internal consistency was calculated using Cronbach's alpha, known-groups validity was assessed, and convergent validity was established through examining the relationship with a widely used scale, the Perceptions of Interprofessional Collaboration Model - Questionnaire (PINCOM-Q). The 13-item scale had a one-factor solution, showed good internal consistency, and demonstrated known-groups validity. Strong correlations were reported for the PINCOM-Q entire scale and subscales coping, social support, communication, and organisational aims. These results support the theoretical conceptualisation of the construct underlying the scale and underline the potential of the scale in assessing and evaluating interprofessional collaboration in this field.