Many students struggle with mental health issues. Training on mental health is one way for schools to equip personnel with the tools needed to help and support students. We evaluated Youth Mental Health First Aid training offered to Illinois K-12 public school personnel, including school administrators, teachers, nurses, and other support staff. The training taught participants about mental health and ways to support students. We conducted field observations of two trainings and administered pre- and post-tests to evaluate the program. Ninety-one training participants responded to a pre-test before the training, and 48 completed both a pre- and post-test. Our evaluation found that participants gained mental health knowledge from training and reported increases in responsiveness and preparedness to help youth with mental health concerns.