Summary With rapidly changing and complex social problems, social workers’ political participation has received increasing attention in promoting social justice and human rights. However, limited studies have examined significant factors that motivate social workers’ voluntary political participation in South Korea. Furthermore, little is known about how significant factors differ by the different types of voluntary political participation. Drawing on the civic engagement model, this study attempted to fill this research gap by analyzing nationally representative data collected from 4,375 social workers in South Korea in 2020. Findings For the resource domain, social workers’ political information was a significant factor to motivate all types of voluntary political participation especially greater for voting and lobbying. For the psychological engagement domain, social workers’ interest in politics was a strong factor in voting and campaigning. Political efficacy was a significant factor in lobbying and protest activities. When social workers had a radical political ideology, they were more likely to engage in protest activities. For the recruitment network domain, social workers’ membership in a political party significantly increased all types of voluntary political participation except for voting. Applications This study suggests that resources, psychological engagement, and recruitment networks are essential for promoting Korean social workers’ voluntary political participation. However, the effects of the three domains can vary across the different types of voluntary political participation Therefore, social workers should receive a wide range of opportunities to learn and engage in varying types of voluntary political participation through effective social work education, organizational support, and community partnerships.