The scale development and exploratory and confirmatory factor analyses of the Protective Factor Index (PFI) is described. The PFI is a 13-item component of elementary students’ report cards that replaces typical items associated with student behavior. The PFI is based on the Construct-Based Approach (CBA) to school counseling, which proposes that primary and secondary prevention activities of school counseling programs should focus on socio-emotional, development-related psychological constructs that are associated with students’ academic achievement and well-being, that have been demonstrated to be malleable, and that are within the range of expertise of school counselors. Teachers use the PFI to rate students’ skills in four construct-based domains that are predictive of school success. School counselors use teachers’ ratings to monitor student development and plan data-driven interventions.