Despite Algeria’ rich cultural and ethnic diversity, research on these concepts, particularly within the educational context, is remarkably scarce. This study sought to examine the direct effects of National Identity (NI) on Ethnic Identity (EI) and Multiculturalism (M), as well as the indirect effect of NI on EI through M. To achieve this aim, the study employed the national identity questionnaire of Yuan and Li (2019), the ethnic identity questionnaire of Yuan and Li (2019), and the multiculturalism scale of Fuertes et al. (2000). The instruments were validated through Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) before being administered to 467 English as foreign language (EFL) university students. The findings indicated non-significant direct effect of National Identity (NI) on students' Ethnic Identity (EI), whereas NI significantly impacted Multiculturalism (M). Furthermore, M significantly influenced students' EI and mediated an indirect effect of NI on EI. The results also revealed noticeable differences across gender, age, and academic level groups for NI and M. For EI, statistical differences were found across gender and level groups. Notably, all comparisons in NI, except for gender and level variables, were statistically significant. Additionally, EI and M identified significant differences between age and level, gender and age, gender and level so as the combined gender-age-level groups. To provide a comprehensive understanding of the research findings, the study outlines its limitations and highlights new directions for future research.