The present study was conducted to design and validate a scale for assessing the spiritual health of primary school children. This research employed a developmental–instrumental design. The statistical population consisted of all students in grades four to six in primary schools of Namin, Sarein, Nir, Germi, and Hir counties during the 2024–2025 academic year (approximately 2,800 students). A sample of 338 children (182 girls and 156 boys) was selected through multi stage cluster random sampling. Initially, 42 items were developed based on theoretical foundations and interviews with eight experts; following content validity assessment by 12 specialists, 34 items with an average CVI of 0.87 were retained. Preliminary qualitative analysis, exploratory and confirmatory factor analyses, internal consistency, and test–retest reliability were employed to evaluate the psychometric properties of the instrument. The KMO value was 0.926 and Bartlett’s test was significant, confirming sampling adequacy. Exploratory factor analysis extracted four factors—Connection with God, Connection with Self, Connection with Others, and Sense of Meaning and Purpose—with eigenvalues greater than 1, explaining approximately 62% of the total variance. Cronbach’s alpha coefficients ranged from 0.79 to 0.92 for the subscales and was 0.90 for the whole scale. Confirmatory factor analysis also indicated a good model fit (χ²/df = 1.12, RMSEA = 0.019, CFI = 0.93). Convergent validity (AVE > 0.50, CR > 0.70) and discriminant validity (Fornell–Larcker criterion) were confirmed. The two week test–retest reliability was satisfactory (r = 0.84). Overall, the developed scale demonstrated strong content, construct, and reliability indices and can be used as a valid instrument for assessing spiritual health among Iranian children in educational, psychological, and school based planning contexts. Nonetheless, it is recommended that future studies employ more geographically diverse samples to enhance generalizability.