This PROSPERO registration (PROSPERO ID: CRD420261336380) describes a systematic review that will synthesize global evidence on the associations between menstrual health and a wide range of health and social outcomes, including education, employment, physical health, sexual and reproductive health, mental health, and wellbeing. By bringing together and critically appraising existing research, the review aims to provide a clearer understanding of the impacts of poor menstrual health and identify priorities for future research, policy, and investment.