Firearm-related suicide is a preventable yet leading cause of death in the United States, and screening for access to firearms in clinical settings is rare. The lack of screening in clinical practice may be compounded by the fact that clinicians are not often trained to effectively screen for access to lethal means. This article evaluates the effectiveness of the novel Engaging in Lethal Means Safety (ELMS) suicide prevention program. ELMS is a theoretically driven, empirically supported lethal means safety training program that trains mental health first responders in engaging clients in discussions of lethal means safety with a particular focus on firearm access and storage. Pretest, posttest, and one-month follow-up assessments measured knowledge of lethal means, confidence, and comfort in screening for access to lethal means, and future intent to counsel on means safety measures. All constructs increased significantly at posttest. Confidence was sustained at posttest. Comfort and intent to counsel levels decreased at follow-up but not to pretraining levels. Booster sessions are recommended for future iterations of the program to further sustain overall effects. Further, additional research using a treatment control is encouraged.