Integrating the United Nations Sustainable Development Goals (SDGs) into higher education programs, rather than treating them as add-ons, is essential for fostering genuine engagement with sustainability and driving transformational change across industries. However, evaluating whether the SDGs are meaningfully integrated into a program--and validating this integration--remains a challenge. This article presents an approach to authenticate the integration of the SDGs into higher education fashion curricula, using the Bachelor of Fashion and Textiles (Sustainable Innovation) at RMIT University, Australia, as the case study. Through cooperative inquiry, we employed a multi-level mapping approach to validate the SDG integration. This included a university-wide SDG mapping process using Elsevier's SDG keyword approach, program-level analysis, and a course-specific evaluation based on staff self-assessments. Our findings revealed differences in what the University high-level mapping identified, compared to the program staff self-assessments. This provided a two-way validation for both the SDG mapping exercise and the curriculum. It also became a useful reflective tool for program staff, as it highlighted how courses within a program are interconnected through the SDGs. The approach is not only applicable within fashion education but could be applied to other programs and disciplinary contexts to authenticate SDGs integration and to support ongoing curriculum development.