Third-sector community organisations are important sites for learning, especially for the most excluded groups in society. However, scant attention has been paid to the various factors shaping educational provision in community contexts, and how these interact to shape the provision available to marginalised populations. This article presents new evidence addressing this gap, through drawing on interview data from practitioners working in the UK homelessness sector. It identifies a range of factors shaping educational provision in these community contexts. These are: service user need and demand; staff roles and capacity; organisational purpose and structures; national policies; support from other adult education providers; non-governmental finance; and volunteers. With some modification, and placed within an overarching critical realist framework, it is argued that these findings are consistent with Boeren's comprehensive lifelong learning participation model. The article concludes that so long as government policy and related funding continues to ignore and fails to support educational provision in these settings, it will remain piecemeal and highly contingent on the contribution of volunteers and short-term funding.