Background <p>Stakeholder-related methodologies for low- and middle-income countries (LMICs) have primarily focused on stakeholder engagement or identification of specific, well-defined populations. Current stakeholder mapping research methods do not provide sufficient sampling processes for defining and implementing a sampling frame for poorly defined populations. In this paper we develop a unique stakeholder mapping methodology and apply it to the Transforming health: The role and impact of women's leadership in the health sector (THRIVE) study, aimed at generating evidence to support investment in women’s leadership in global health decision-making in reproductive, maternal, newborn, child, and adolescent health, and nutrition (RMNCAH-N) and immunization across sub-Saharan Africa (SSA). Though current literature has examined challenges women have faced to reach leadership roles, there are no methods for systematically identifying women leaders, and leaders in RMNCAH-N and immunization have not been uniformly well-defined or systematically documented. Consequently, understanding the impact of women’s leadership on health and healthcare policies is lacking.</p> Results <p>We developed a stakeholder mapping methodology to ensure accurate identification and representation of leaders in RMNCAH-N and immunization in Sub-Saharan Africa who could serve as a “sampling universe” for further investigation into the impact of women leaders. We began by defining what constituted a “leader” and “leader-adjacent” individual. Using a matrix, we refined the target sample of stakeholders and created uniform inclusion criteria. Stakeholder mapping was guided by the following strategic steps for each SSA country: screen government webpages; contact UN/multilateral agencies; conduct a systematic Google and social media search; identify relevant academic and grey literature; contact professional and personal connections in SSA; cross-check leads against a pre-defined matrix of stakeholder levels; and in-country validation. Inputs were collated into a shared Excel sheet. At the end of the stakeholder mapping exercise, we had systematically identified 3,901 leads. On average, 81 stakeholders were identified for each country. Approximately 38% (<i>n</i> = 1353) of the identified individual stakeholders were women.</p> Conclusions <p>This paper’s focus on creating a sampling universe of women leaders in RMNCAH-N and immunization in SSA fills a gap in current operational and implementation research. The insights derived from the adaptation and application of this methodology highlight the value of a structured approach to capturing the complexities of stakeholder and leadership dynamics in global health, particularly when applied to systematically map health topics or disciplines that lack databases or public records.</p>