--- - |2+ Background Increases in emergency department (ED) visits for pediatric mental health care point to a need to understand the impact of mental health services in relation to emergency‐based care. This systematic review examined the impact of mental health services delivered in outpatient, primary care, community and/or school settings on ED use and costs for ED‐based mental health care. Method Two electronic databases and gray literature were searched. Eligible studies consisted of randomized/controlled clinical trials or cohort studies examining the effects of mental health services on ED use and costs for this care. Two reviewers independently screened the studies for relevance and study quality. Relative risks (RR), risk differences (RD), or mean differences (MD) were calculated for each study's primary outcome with 95% confidence intervals (CI). Meta‐analysis was deferred due to substantial heterogeneity. Results Six studies were included. Overall risk of bias in the studies ranged from low, unclear, to high. The majority of programs had no effect on ED visits for mental health care. A school‐based program was found to reduce the risk of ED visits for any reason during use (RD, −8.0%; 95% CI: −15.2%, −0.9%); however, these visits were not specific to mental health. Three studies examined costs. A wrap‐around clinical management program was associated with higher average ED costs per patient per month ($20.07 US dollars) compared to usual outpatient care; other studies reported no cost differences. Conclusions At this time, there is limited evidence to suggest outpatient, primary care, community and/or school‐based mental health services impact ED use and costs for mental health care. Additional studies are needed. - Journal of Child Psychology and Psychiatry, Page 4-13, October 2018.