Break the Cycle of Children's Environmental Health Disparities (Break the Cycle) is an annual collaborative interdisciplinary research and training program involving university students in academic tracks focusing on the impact of adverse social, economic, environmental, and political factors on children's health, development, education, and prospects for their future. The target populations are communities where there is a substantial measure of poverty associated with social, ethnic, racial, and political marginalization, environmental exposures and environmental injustice with high risks to children's health and well-being. Participating students are required to develop projects that focus on preventing or reducing adverse environmental factors or their impact on children's health and promote positive practices to improve the future outcome for children who live in these communities. Student projects cover a wide range of adverse factors and their associated health implications across the lifespan, and propose solutions at an individual, family, community, and societal level, with the potential for a positive intergenerational impact. At the end of the project period, participating students are required to present the results of their work at a national conference and then write a manuscript for publication. The papers in this publication represent the work of students who participated in the 15th Annual Break the Cycle program 2019-2020. The phrase Break the Cycle in this context uses the ecological construct of the cycle of environmental health disparities and offers a framework for tackling health disparities and promoting health equity among children who are vulnerable as a consequence of adverse social, economic, environmental and political factors.