Numerous studies have evidenced moral distress among midwives; however, to date no research synthesis on causes of moral distress among midwives has been conducted. A scoping review was carried out to identify, comprehensively map, and categorize possible causes of moral distress among midwives, and to identify knowledge gaps. Six data bases were searched using Boolean logic. To be included, studies had to (a) present empirical findings on (b) causes of moral distress (c) among midwives (d) in English, German, French, or Italian. We included a final set of 43 studies. The vast majority of studies came from high-income countries (83.7%) and used a qualitative approach (69.8%); 48.8% of the studies were published in the past 5 years. Identified single reasons of moral distress were grouped into eight broader clusters, forming a coherent framework of reasons of moral distress: societal disregard, contemporary birth culture, resources, institutional characteristics, interprofessional relationships, interpersonal mistreatment of service users, defensive practice, and challenging care situations. These clusters mostly capture moral distress resulting from a conflict between external constraints and personal moral standards, with a smaller proportion also from an intraindividual conflict between multiple personal moral standards. Despite projected increases in demand for midwives, the midwifery workforce globally faces a crisis and is experiencing substantial strain. Moral distress further exacerbates the shortage of midwives, which negatively affects birth experiences and birth outcomes, ultimately rendering it a public health issue. Our findings offer points of leverage to better monitor and alleviate moral distress among midwives, contributing to reducing attrition rates and improving birth experiences and birth outcomes. Further research is essential to explore the issue of ecological moral distress, develop evidence-based interventions aimed at alleviating moral distress among midwives, and evaluate the effects of both individual and system-level interventions on midwives, intrapartum care, and service users' outcomes.