Child corporal punishment is a prevalent public health problem in the U.S. Although corporal punishment is sustained through parents’ perceptions of social norms supporting this discipline behavior, little research has investigated where these normative perceptions come from. To fill this gap, we conducted 13 focus groups including 75 low-income Black, Latino, and White parents across five states in the U.S. Results revealed that one influential source of Black and White parents’ perceived norms was their positive framing of corporal punishment experiences during childhood. Furthermore, Black parents formed normative perceptions based on identification with parents in their racial/ethnic group, while White parents did so with parents sharing the same generation. Results are interpreted in light of the false consensus effect and self-categorization theory. In contrast, Latino parents viewed their childhood experience of corporal punishment as negative and distanced their parenting practices from those practiced in their countries of origin, suggesting an influence of acculturation. Their perceived norms were likely transmitted through interpersonal communication within their social networks. These findings shed light on how social norms are formed and in turn guide parents’ use of corporal punishment as a tool to discipline children.