Informal science education (ISE) is a popular pursuit, with millions of people visiting science museums, science centres, zoos, botanic gardens, aquaria, science festivals and more around the world. Questions remain, however, about how accessible and inclusive ISE practices are. This article reviews research on participation in ISE through the lens of social inclusion and equity and suggests that, as a field of practice, ISE is exclusive, with relatively little empirical or theoretical research on equity compared to "formal" science education. This article contributes to science education scholarship by exploring equity in ISE, bringing together international research on ISE equity issues to examine what an access and equity framework for ISE might entail. It draws on theoretical perspectives from research on social justice, social reproduction and pedagogy to adapt a three-part access framework, focusing in turn on infrastructure access, literacy and community acceptance, to develop an access and equity framework for ISE.