This study examined the viability of a brief, parent-reported strengths and needs assessment as the first step in a multiple-gating approach to proactive positive behavior support for families. The Positive Family Support–Strengths and Needs Assessment (PFS-SaNA) was designed to collaboratively engage parents early in the school year in a home–school coordinated Positive Family Support (PFS) system. In this study, we evaluated the reliability and validity of the PFS-SaNA in the context of public middle schools. Findings suggest that the 14-item, unidimensional PFS-SaNA shows convergent validity with teacher ratings of risk. It can be easily and cost-effectively used by school personnel when parents register their children for school at the beginning of each school year.