Mental health literacy is fundamental to improving knowledge about mental health, decreasing stigma, and, therefore, enhancing help-seeking behaviors. The purpose of this cohort study is to evaluate the impact of a mental health literacy program on preservice teachers' knowledge, attitudes, and help-seeking efficacy. Sixty preservice teachers in a Canadian university participated in a professional development day and completed a survey of their mental health knowledge, attitudes toward mental illness, and help-seeking efficacy. Compared with baseline data, results demonstrated significant and substantial improvements on all three outcomes immediately following the session and after 3 months. Provision of mental health literacy education among preservice teachers may be an effective approach to help them better address student mental health needs in their future teaching career.