Background: Given the significant gap in tailored assessment tools, this research seeks to adapt the Self-concept (Form 5-AF5) questionnaire for young students with intellectual disabilities, employing an inclusive approach. Method: Twenty-three disability experts initially assessed questionnaire suitability, leading to revisions for clarity. Cognitive interviews with eight students with intellectual disabilities clarified questions, and both original and adapted questionnaires were administered to students with and without intellectual disabilities for equivalence verification. Results: The adapted scale showed good internal consistency. The correlation between scores of students without intellectual disabilities on original and adapted questionnaires exceeded 0.70. Students with intellectual disabilities reported higher levels of academic self-concept than their peers without intellectual disabilities. Conclusions: The adaptation of the Self-concept (Form 5-AF5) questionnaire in this research facilitates the comparison of diverse student populations, as demonstrated by the alignment of results between the original and adapted questionnaires in the general student population.