This paper examines how advocacy organisations organise engagements to advance corporate social and environmental accountability. We present an in-depth case study examining how an influential Dutch advocacy organisation enacted its engagement with companies to promote the adoption of corporate social responsibility (CSR) reporting and management practices. Drawing on the construct of strategic framing, we unpack the characteristics that supported the development of a resonant engagement frame that set the boundaries and expectations around the organisation’s engagement with companies. We unveil how several internal organisational deficiencies impeded the quality of these engagements, thereby threatening this frame resonance. The paper extends our understanding of the nature and role of strategic framing in the construction of CSR reporting and advances our limited knowledge of how CSR advocacy organisations’ internal operations impact on their engagement efforts. This allows us to better comprehend how these organisations can set engagement agendas and mobilise support for collaborative CSR change initiatives.