Purpose: The purpose of this study is to examine the impact of psychological safety on transformative learning in the workplace. This study focused on psychological safety as a specific practice that may or may not independently contribute to transformative learning outcomes. Design/methodology/approach: Data was gathered from 132 employees in one US manufacturing company through a survey asking about the perception of psychological safety and the experience of transformative learning. A mediation analysis was conducted to test the effects of transformative learning processes -- social support, attitude toward uncertainty and criticality -- on the relationship between psychological safety and transformative learning outcomes. Findings: The results of this study showed that psychological safety led to transformative learning outcomes mediated by transformative learning processes including social support, attitude toward uncertainty and criticality. Originality/value: Existing literature reveals little about the mechanism of how transformative learning occurs in the workplace. This study contributes to the field of human resource development by explaining the relationship between psychological safety and transformative learning, as well as first attempting to use transformative learning as a viable construct in workplace research.