Drawing on club theory, this study examines the challenges and opportunities facing a sustainability certification program, the Green Key scheme, in terms of its recruitment and retention of members within the Dutch tourism and hospitality industry. Extant literature on sustainability certification in this industry tends to focus narrowly on motivations and retention problems at the firm level, or else on drivers of or barriers to the adoption of sustainability certification schemes. The links between scheme design characteristics and scheme effectiveness and their implications for recruitment and retention thus have remained relatively unexamined. To address this gap, this study proposes a theoretical framework that highlights how different design features of sustainability certification schemes might inform the recruitment and retention challenges that scheme managers often face.