Examining the concepts underpinning the reasoning processes of social worker's decision‐making provides important insights into how social work practice is undertaken. This paper examines one of the major discourses used by social workers in decision reasoning in a non‐governmental organization child protection context in Aotearoa/New Zealand: family maintenance. This study found that family maintenance as a concept was strongly privileged by social workers. This resulted in attempts to preserve families and created a hierarchy of preferred decision outcomes. A preference for family maintenance was supported by legal, moral, psychological and Māori cultural concepts. This pattern of constructs underpinned the ‘weighing up of harms’ when considering removal, and generally reflected a child welfare orientation. In addition to this, it was found that ‘family’ was broadly defined, and could include people who had a relationship with the children, or Māori definitions of extended family, in addition to legal ones.