OBJECTIVES: The COVID-19 pandemic led to public health crises beyond the direct casualties from the virus itself. This study assesses the impact of COVID-19 on suicide rates in South Korea, which implemented effective policy interventions against COVID-19 and has one of the highest suicide rates among member states of the Organisation for Economic Co-operation and Development (OECD). STUDY DESIGN: A county fixed effects model. METHODS: We analyze county-level data covering the 2017-2022 period from the National Statistical Office of Korea and use a county fixed effects model. The primary outcome is the suicide rate per 100,000 population. Our main analysis compares pre-pandemic suicide rates (2019) with those during the pandemic (2020-2022) at bimonthly frequency, focusing on the population aged 20-59 years. RESULTS: We find that, in contrast to the initial global concerns about potential increases in suicide because of pandemic-related stress, suicide rates significantly decreased during the pandemic. However, this trend was not uniform: young women experienced fluctuating suicide rates, highlighting a demographic-specific impact. The study also finds that both people who died by suicide and people who died of other non-suicide causes were more likely to have a college diploma and were less likely to be married. Additionally, there are mixed results regarding the location of death. Overall, the pandemic appears to have had a complex effect on suicide behaviors in South Korea. CONCLUSIONS: The findings underscore the need for targeted mental health interventions, especially for vulnerable groups such as young women. The findings also emphasize the importance of considering demographic-specific responses in public health strategies to better address the mental health consequences of large-scale crises.