Home-visiting mental health professionals (HMHPs) have an important role in identifying suspected child maltreatment in the community. However, it is unclear how professionals in Hong Kong differentiate acceptable discipline behaviours from reportable forms of abuse, and how their characteristics may influence their view. This study examined HMHPs' views on acceptable versus unacceptable parent discipline behaviours. Using Q-methodology, 50 HMHPs in Hong Kong sorted 52 statements on parent discipline behaviours along a continuum ranging from ‘Most Unacceptable’ to ‘Most Acceptable’. By-person factor analysis was conducted to uncover prevailing views based on their sorts. Three unique viewpoints in differentiating discipline behaviours from abuse were uncovered, which varied based on how HMHPs prioritised children's physical safety, mental wellness and parental intention. Different views were supported by professionals with different characteristics and occupational backgrounds.