This descriptive study was conducted in a private international school in Abu Dhabi, UAE, the aim of this study was to investigate the students’ understanding and acceptance of cultural diversity in the school environment and explain the impact of cultural diversity in language and belief on their behaviour and identity. A convenient sampling of 230 high school students (grades 9–12) was selected, and 85 students voluntarily participated to respond to an electronic self-concept questionnaire, whose validity and reliability were confirmed. Quantitative data was collected on students’ agreement or disagreement using the 5-Likert Scale to answer the research's main questions: What is the level of students' understanding of cultural diversity in school? What is the impact of cultural diversity in language on students’ identity and behaviour? What is the impact of cultural diversity in beliefs on students’ identity and behaviour?. Data was analyzed statistically using SPSS, and the results pointed to a generally favourable view toward cultural diversity in language and belief in school. It revealed that the majority of students showed a high level of understanding and acceptance of cultural diversity, and that was clearly reflected in their responses and how they reacted to some situations. On the other hand, results showed that there was no clear evidence of a significant impact of language cultural diversity on students’ identities, while it was clear enough to show that it had an impact on their behaviour to show that language is not a barrier to communicating and to being interested in learning other languages. The last part of the results and findings explained that there was a positive impact of cultural diversity in beliefs on students’ identity and behaviour. The study intended to contribute to the effectiveness of cultural diversity and communication diversity in school environments in the United Arab Emirates by investigating the current situation.