Youth Mental Health First Aid (YMHFA) is a training program designed to help adults working with children and adolescents identify and respond to youth who are experiencing mental health problems or are in crisis. YMHFA is being implemented in a number of educational, child welfare, and juvenile justice settings across the country with little evidence of its effectiveness. As part of a broader mental health program implemented in five schools in a southeastern county in the USA, YMHFA was provided to school personnel over a 2-year period. This study presents the results of a pretest/posttest evaluation of the YMHFA training. In general, results provide preliminary evidence of the effectiveness of the YMHFA training. More specifically, results highlight the importance of YMHFA training for personnel who have never received mental health training/education and for those who do not have experience working with vulnerable youth populations.