The operationalization of school climate is inconsistent, adding to an unwieldy existing body of climate instruments, bringing into question measurement validity concerns. Further, there is minimal literature regarding if comparisons can be made between different school sectors (i.e., public, private, charter). We seek to understand if a commonly used school climate scale (5Essentials of School Climate and Culture Survey) in a representative sample of teachers can be used to make valid comparisons between sectors, and if items might exhibit bias toward any school type using a Differential Item Functioning (DIF) approach. Although not misfitting, a great deal of significant DIF at different magnitudes exists in the items. We propose caution should be used when interpreting research comparing between and across school sectors without explicitly exploring measurement validity.