When embedded within a continuum of mental health services including both prevention and treatment, school-based mental health identification programs can promote improved academic and mental health functioning among students. This article describes the scientific status of assessment instrumentation that may be used for early mental health identification in schools. Currently available instruments are described in terms of their ability to accurately detect youth with mental health problems. Implications for selecting mental health screening and assessment instruments and integrating them into schools are discussed. Finally, a range of approaches to early identification in schools as well as some of the broader ethical and practical issues related to the integration of these strategies into a school-wide continuum of services are presented.