Students can deal with diverse classroom contexts neutrally, proactively, and constructively, or perceive them as irritating or even threatening. Diversity acceptance is the individual’s ability to deal with social diversity in a positive and accepting manner. It captures the individual’s dealing with diversity globally (across all facets of diversity). This ability is of practical importance when dealing with diversity challenges in schools. Two studies are presented in this paper: Study I examines adolescents’ and young adults’ acceptance of culturally, religiously, or ritually different groups. Study II presents initial results of the DWD-S scale, a newly developed instrument for the global measurement of diversity acceptance across multiple facets for the school context. The scale was adapted through three studies: item adaptation through interviews with students (Study A) and factor analyses (Study B). Through the iterative exploratory factor analyses, 50 models were generated and compared. The CFA confirmed a model with four factors and 13 items. Considering the relevant parameters, the scale has a good model quality. The DWD-S shows a good reliability. Construct validity is assessed in Study C. The scale can be used as a research tool to investigate the development, changeability, and other implications of diversity acceptance in adolescents aged 13 and older.