Marine spatial planning (MSP) was developed as a place-based, integrated marine governance approach to address sectoral and fragmented management issues and has seen significant evolvement over the past two decades. MSP has rapidly become the most commonly endorsed management regime for sustainable development in the marine environment, with initiatives being implemented across multiple regions of the globe. Despite its broad and growing acceptance and use, there are several key challenges that remain, both conceptual and practical, that are negatively impacting the realization of MSP’s potential. These include institutional shortcomings, the exclusion of stakeholders, a failure to account for the human and social dimensions of marine regions, the marginalization of different types of knowledge, and the growing need to adapt to global environmental change. Although studies have examined the emergence of MSP in different geographical and institutional contexts, there is a lack of comparative analysis of how initiatives are progressing and if the foundational aims of MSP are being achieved. There is a need to analyze the degree to which MSP initiatives are responding to the environmental challenges that they have been set up to tackle and, as marine plans are setting out long-term visions for marine management, to understand if current initiatives are fit for purpose. This article responds to these concerns and reviews the evolution of MSP within 12 regional ocean areas. We utilize the term regional ocean areas to illustrate the geographical spread of MSP, with examinations conducted of the approach to MSP that specific nations within each of the 12 chosen clusters have followed. By critically assessing how MSP is progressing, it is possible to shed light on the opportunities and challenges that are facing current initiatives. This can help to reveal learning lessons that can inform future MSP systems and guide initiatives along more sustainable pathways.