Children’s freedom to navigate their environment independently is associated with greater physical activity and enhanced physical, social and emotional development. Parental fear is a recognized barrier to children’s independent mobility, however there are scant reliable tools to measure this fear. We report on the development and validation of two brief scales to assess parental fear, ‘Parental Fear’ (PF) and ‘Fear of Strangers’ (FoS). Specifically, we aimed to: confirm the construct validity of the scales; establish discriminant validity between PF, FoS and parents’ mental health (as measured on the Kessler-6); assess the internal consistency and test–retest reliability of PF and FoS; and establish predictive validity with children’s independent mobility. Development was conducted in five steps: (1) item pool generation; (2) a development study; (3) a validation study in a statewide sample (Victoria, Australia) of parents of children (9–15 years, n = 1973); (4) a reliability assessment; and (5) an examination of predictive validity with respect to children’s independent mobility. Two brief, robust, and internally consistent measures were established (PF, four-items; FoS, five-items), which discriminated from parent’s mental health. Both measures had strong internal consistency and temporal stability. Predictive validity was established; parents who reported higher PF and FoS were less likely to allow their children to engage in a range of independent activities without an adult. These scales contribute novel valid tools for use in public health and intervention research aimed at reducing parental fear as a barrier to children’s independent mobility and resultant physical activity.