1 In the wake of the COVID-19 pandemic, the mental health needs of early adolescents have dramatically 2 increased – suicide attempts have increased by 50%, depression and anxiety has increased by 40%, and 3 hospitalizations due to mental health concerns have increased by 30%. Among adolescents receiving treatment 4 for mental or behavioral health challenges, 56% receive services in K-12 schools – meaning that school-based 5 mental health supports are one potentially viable setting for addressing mental health needs of students (Green 6 et al., 2013). However, these services require school staff to have the knowledge and ability to identify and 7 implement appropriate mental and behavioral health needs of students in their schools. Schools located in rural 8 and small communities have particular difficulties accessing appropriate resources to support student mental 9 health but online technology presents a promising solution to this problem. To understand how online supports 10 may improve the quality of school-based mental health services and adolescent mental health outcomes, the E- 11 IMPACTS trial will rigorously evaluate the integration of two online activities: first (1), an online evidence-based 12 mental and behavioral health screening tool, called the Early Identification System (EIS) and second (2), a virtual 13 professional learning community and coaching following the Extension for Community Healthcare Outcomes 14 (ECHO) model. ECHO has been used to improve patient outcomes in other health contexts and demonstrates 15 promising impact when applied in school-settings to address mental and behavioral needs of students. Building 16 on this prior work, the E-IMPACTS trial will use a school randomized controlled trial with 42 middle schools 17 located in VA, MO, and SC. The trial will measure immediate impact (baseline-post) on adolescent mental health 18 outcomes inclusive of internalizing and externalizing behaviors (Aim 1) as well as staff reaction to training, their 19 knowledge and implementation of evidence-based mental health interventions (Aim 2) while examining cost and 20 school-level factors moderating implementation of evidence-based practices (Aim 3). Schools will be randomly 21 assigned to receive both EIS and ECHO supports (n = 27) or to an active control condition with access to EIS 22 alone. School staff will use EIS to screen adolescents for mental or behavioral health needs (~21,000 students) 23 and school staff (~1350) will complete surveys (baseline-post) assessing knowledge and implementation of 24 mental health practices. Coaching provided through ECHO will focused on school-wide prevention or early 25 intervention strategies for addressing mental or behavioral health needs observed obtained via EIS data. Results 26 will advance knowledge about how these online activities can advance implementation of school-based mental 27 health activities and outcomes.