Higher Education Mental Health Act of 2021 This bill requires the Department of Education to establish an Advisory Commission on Serving and Supporting Students with Mental Health Disabilities in Institutions of Higher Education. The commission must conduct a study and report on services available to students with mental health disabilities in institutions of higher education (IHEs) and the effectiveness of such services in supporting these students; the impact of policies and procedures, such as reasonable accommodation and disciplinary policies, that help or hinder the goal of providing equal opportunity to these students; the use of protected health information of these students by IHEs; the impact of providing mental health services on a student's academic performance, well-being, and ability to complete college; conclusions on the major challenges facing these students; and recommendations to improve the overall education, retention, and graduation of these students.