Background and Objectives: The Lao PDR (Laos) has the highest rate of child-stunting (low height-for-age) in South-East Asia despite a higher gross national income compared to other countries. Stunting has significant implications for a country’s future economic prosperity and productivity and remains a priority global health issue. A paradigm shift is needed if the burden of childhood stunting is to be reduced both in Laos and globally. This requires a better understanding of the underlying drivers of childhood undernutrition within context, and how these drivers interact to produce the symptomatic outcome of child stunting. Using community-based system dynamics (CBSD), a participatory approach that builds stakeholder capacity to learn and address complex problems, this research sought to better understand the fundamental dynamics of child-stunting in Laos and build stakeholder capacity in systems thinking. Methods: The CBSD approach was adapted to the context of Laos incorporating literature reviews, exploratory system models, and two stakeholder group model building workshops in Laos. Current research and mental models of stakeholders were mapped, and a combination of synthesis and triangulation employed for data aggregation. Results: Stakeholders developed five causal-maps of the child-stunting system, along with narratives articulating their understanding of child-stunting determinants in Laos. A thematic analysis of the data identified three key gaps between stakeholder knowledge, published literature, and socioeconomic data. Traditional practices and post-partum dietary restrictions, antenatal care and treatment by health care practitioners, and the education system were identified as core underlying drivers of child-stunting in Laos. Conclusions: This research provides insights into the complexity of childhood stunting in Laos and delivers an adapted CBSD approach that can be applied to other complex public health problems in low-resource settings. Scaling up this research provides the opportunity to bridge the knowledge-policy gap and inform evidence-based, high-impact policies with improved health outcomes.