Thirdhand smoke is the toxic residue that remains on walls, floors, furniture, toys, clothing, skin, hair, and other surfaces long after smoking has stopped. In the face of increasing evidence about the toxic nature of thirdhand smoke and its impact on human health, the Thirdhand Smoke Research Consortium was established by California’s Tobacco-Related Disease Research Program (TRDRP). The Consortium brings together researchers from a variety of scientific disciplines and institutions throughout California to advance our understanding of the relationships among thirdhand smoke exposure and human health. In 2011 the first seven Consortium projects were funded by TRDRP. As the body of research has grown, the need to disseminate information to stakeholder groups and California’s diverse communities has intensified. In 2018, the Resource Center was one of the Consortium projects selected for funding by TRDRP, with the express purpose of educating the public about thirdhand smoke exposure and health. The mission of the Thirdhand Smoke Resource Center is to share information, resources, and technical support with California’s residents, communities, businesses, health care professionals, and policymakers about the toxic legacy of tobacco smoke residue and to achieve indoor environments that are 100% free of tobacco smoke toxicants. An interdisciplinary, international group of researcher and public health practitioners contribute to the work of the Resource Center, which is physically located at San Diego State University.