Objective: The objective of this study was to investigate the Korean public’s recognition of autism spectrum disorder (ASD), revealing underlying factors regarding perception relative to etiology and treatment of ASD, and examining variables related to those factors. Methods: An online survey was held to investigate mental health literacy (MHL) on ASD of the general public in Korea. A total of 673 adults participated and completed questionnaires on socio-demographic characteristics and if they know someone with ASD. Next, participants were provided with a vignette describing a child with ASD. Only those that recognized there was a problem with the child moved to the next part which asked their perception regarding etiology and treatment of ASD. Results: According to our study, approximately 25% of participants correctly recognized the child in the vignette as having ASD. Perception regarding etiology and treatment of ASD varied among socio-demographic characteristics. Participants acquainted with someone with ASD and correctly recognized ASD held mixed perception regarding cause and treatment. Conclusion: This study investigated MHL of ASD in Korea. The result reveals there is much room for improvement relative to raising awareness on MHL of ASD. Intervention considering socio-demographic characteristics and acquaintance with ASD are needed.