Concerns about participation in science engagement, communication and education have typically been framed in terms of ‘barriers’ to participation. Such barriers include cost, location and interest in science.  Doubtless barriers affect participation, but by foregrounding a focus on single barriers, questions of complexity, power, dominance and domination recede into the background.  This paper explores the question of exclusion and non-participation in one area of science engagement; informal science learning.  Informal science learning environments (ISLEs) such as science museums, science centres, zoos, botanic gardens, aquaria and science festivals are significant features in the science communication and engagement landscape.  Not everyone, however, may perceive ISLEs as offering valuable experiences and not all visitors may experience the same benefits.  Instead, as I argue in this paper, attitudes towards and experiences of ISLES may differ in ways that are inequitable and, as this study suggests, marked by social positions such as ethnicity and class.  Drawing on research with four community groups and their visits to three different ISLEs, this paper uses theoretical concepts from Bourdieu to examine how social exclusion and non-participation happens in practice during ISLE visits.