This paper seeks to establish the role of financial literacy, behavior intention, and perceived control in two key retirement savings behaviors: voluntary savings and investment plan change during the onset of COVID-19. The study explores the heterogeneity of results within a representative sample of members in Thailand's Government Pension Fund (GPF) by matching survey responses to an administrative sample data of member behavior. We establish that social norms are the strongest positive predictor of intention to perform both behaviors, and in turn behavior intention and perceived control over behavior are significant in explaining actual behavior. In addition, objective financial literacy is a significant positive predictor of both behaviors, notably commencing the behavior, as well as a negative predictor of stopping. The results suggest that financial institutions (e.g., pension funds) wanting to increase member savings and promote the role of investment strategy review may usefully focus on developing member behavioral intentions and improve financial literacy. We also note heterogeneity in results which highlights the challenge faced by large institutions such as Thailand's GPF to efficiently cater to a diverse membership.