Philosophiae Doctor - PhD / Access to life-saving commodities and related services for women and children is a fundamental component of universal health coverage. However, countries confront numerous intractable challenges, such as aligning regulatory practices, enhancing health workforce capacity, and effectively managing supply chains, to ensure essential reproductive, maternal, newborn and child health (RMNCH) commodities and services reach all communities. To address these entrenched obstacles, the UN Commission on Life Saving Commodities for Women and Children (UNCoLSC) in 2012 outlined a series of recommendations to improve access to 13 low-cost and high-impact commodities. This thesis explores the improvements and remaining barriers to accessing life-saving commodities for women and children in sub-Saharan Africa and Southeast Asia. In addition, this thesis showcases how effective data-informed decision-making can support prioritized RMNCH investments and equitycentered action.