Scotland has significant marine energy resources and is at the forefront of the research and development of wave and tidal marine renewable energy technologies. Much of this research has focussed on the technological challenges of marine renewable energy (MRE) development, and accordingly there has been an important gap in understanding the social implications of the technology. This PhD contributes important new knowledge to the emerging field of the sociology of marine renewable energy. Previous studies have explored the many and varied grounds on which publics might come to support or oppose other low-carbon energy technologies, though to date there has been limited research into whether the same range of factors also inform social responses to MRE. This thesis presents new understanding of social responses towards MRE projects and the social impacts MRE may have on communities. Findings from eighteen months of ethnographic fieldwork, living, working, and coastal skiff rowing, on a Scottish island are presented, along with the results from a series of public dialogue workshops held in six Scottish communities. This innovative twin-track qualitative research approach provides a rich understanding of everyday life and practice in relation to community, environment and energy, and insight into some of the more intangible ways in which MRE projects may affect communities. The research shows that the strong and unique cultural and historical identity of coastal communities, together with the economic fragility of the areas, influences how MRE, and those promoting it, are perceived. Responses to energy projects depend on the perception of change that will occur as a result of the project and vary significantly both within and between communities. The data obtained show that MRE projects that are perceived to positively benefit the local area are welcomed, and that project developers and policy makers should focus as much on ameliorating positive benefits to communities as mitigating negative impacts. Planning processes that appropriately understand and negotiate these concerns are therefore required, in order to engage with communities and maximise the potential opportunities that MRE technologies present for marginal rural communities.