A number of commentators have argued that up until now marine/maritime spatial planning (MSP) research and practice have been dominated by blue economy and environmental concerns and have tended to neglect what might be regarded as social sustainability concerns. To gain more insight into the character and extent of such a gap, as well as how to address it, this article examines how social sustainability has been addressed in peer reviewed scientific articles on MSP between 2005 and 2020. Using search terms such as participation, democracy, social inclusion, social cohesion, equity we systematically identify and review 310 scientific articles that address diverse social sustainability concerns within MSP and marine governance. The review showed that very few papers systematically conceptualised or developed a coherent framework for engaging with social sustainability. Instead, they mostly addressed particular social concerns including participation and engagement, equity and social justice, socio-cultural values and preferences. Marine management and planning efficiency, as well as related instrumental framings of the merits of participation were the key arguments for including these dimensions of social sustainability in MSP. In terms of how to better include social sustainability in MSP, most attention was given to social-cultural mapping and ways to improve social inclusion/participation while also redressing exclusion and maldistribution of outcomes in MSP practice. We conclude that there is a need to deepen and diversify MSP inquiry with respect to social sustainability. In particular, scholars would do well to delve deeper and more broadly in social science literature to find inspiration on ways to understand and elucidate social issues. Here, the enormous body of relevant work on justice, power, critical institutionalism, political ecology and terrestrial planning literatures has hardly been tapped. It is also evident from this review that there is a need for both the academic and practice-based communities to more comprehensively address how the multidimensions of social sustainability interact with each other, as well as with economic and environmental aspects of marine planning and governance. Based on these observations, we highlight a set of suggestions on how to develop MSP research and practice on social sustainability. Most importantly, we argue that more in-depth co-production, linking scholars, practitioners and society actors, is needed.