The Social and Emotional Health Survey-Secondary (SEHS-S) is a widely used self-report measure of adolescents' strengths and positive mental health. However, the SEHS-S does not have a proxy (i.e., parent) informant version. A parent form of the SEHS-S could allow school psychologists to gather additional information about students' strengths for intervention and assessment purposes. The development of this measure included three phases. First, we generated items and refined them in a preliminary study. Next, a subsequent confirmatory factor analysis (N = 613) identified the highest-loading items for scale construction. Finally, a validation study (N = 319) asked parents and their children to complete respective versions of the survey. The final 36-item parent measure had strong loadings and adequate model fit matching the factor structure of the self-report version. The SEHS-S-Parent also demonstrated good reliability and correlations with the self-report version, including predicting child well-being as measured by life satisfaction and emotional functioning. The finding that the child and parent self-report measures were highly correlated suggests that parents might provide helpful information about adolescents' strengths, especially when a self-report is unavailable. Limitations regarding the scale's interpretability and implications of a multi-informant approach are considered.