The school climate measure (SCM) has demonstrated robust psychometrics in regionally diverse samples of high school-aged adolescents, but remains untested among early adolescents. Confirmatory factor analysis was used to establish construct validity and measurement indices of the SCM using a sample of early adolescents from public schools located in Central Appalachia (n = 1,128). In addition, known-groups validity analyzed each SCM domain against self-reported academic achievement and school connection. Analyses confirmed all 10 SCM domains fit the data well with strong internal consistency and factor loadings. Known-groups analyses suggest students who reported higher academic achievement and school connection demonstrated higher perceptions of school climate. Findings provide evidence that extends the use of the SCM to early adolescents and may support school-based policy.