Small-scale artisanal fishery in Ghana has encountered unprecedented challenges in recent decades, including dwindling fish stocks. Correspondingly, the sector’s institutional landscape has evolved to comprise a diverse array of institutions. Drawing on qualitative fieldwork conducted in two fishing communities in Ghana, this paper examines the complex interplay between formal and informal institutions, providing insights into how they work and are perceived. The findings reveal two distinct institutional orders: one based on state law with formal enforcement, and the other rooted in traditional authorities, indigenous knowledge, and religious beliefs maintained through social sanctions and consensus-building. Neither system is fully institutionalized, leading to varying degrees of legitimacy and enforcement, which negatively impact sustainable marine resource management and livelihoods. The paper discusses the potential of co-management approaches that aim to integrate diverse stakeholders and institutions. By addressing the complexities of institutional dynamics, the paper contributes to ongoing policy debates on sustainable fisheries management.