Purpose: In mental health care, patients and their care providers may conceptualize the nature of the disorder and appropriate action in profoundly different ways. This may lead to dropout and lack of compliance with the treatments being provided, in particular in young patients with more severe disorders. This study provides detailed information about patient–provider (dis)agreement regarding the care needs of children and adolescents. Methods: We used the Camberwell Assessment of Need (CANSAS) to assess the met and unmet needs of 244 patients aged between 6 and 18 years. These needs were assessed from the perspectives of both patients and their care providers. Our primary outcome measure was agreement between the patient and care provider on unmet need. By comparing a general outpatient sample (n = 123) with a youth-ACT sample (n = 121), we were able to assess the influence of severity of psychiatric and psychosocial problems on the extent of agreement on patient’s unmet care needs. Results: In general, patients reported unmet care needs less often than care providers did. Patients and care providers had the lowest extents of agreement on unmet needs with regard to “mental health problems” (k = 0.113) and “information regarding diagnosis/treatment” (k = 0.171). Comparison of the two mental healthcare settings highlighted differences for three-quarters of the unmet care needs that were examined. Agreement was lower in the youth-ACT setting. Conclusions: Clarification of different views on patients’ unmet needs may help reduce nonattendance of appointments, noncompliance, or dropout. Routine assessment of patients’ and care providers’ perceptions of patients’ unmet care needs may also help provide information on areas of disagreement.