Civil society organisations increasingly mediate the creation and exchange of evidence in their activities with policy-makers and practitioners. This article extends knowledge on evidence in policy-making settings to civil society contexts. As an exploratory and qualitative study, it shows how nine UK-based organisations working on issues including migration and social welfare hold different perceptions of evidence and its usefulness. A range of related factors involving individuals, organisations, sectors, and issue areas emerge as contingent contributors to these variations. The results suggest that researchers and practitioners seeking to engage with civil society using evidence should consider context-specific values, skills, motivations, and timeliness.