Marine renewable energy is poised to grow in the coming decades, contributing to the shift toward a sustainable energy regime. However, realizing marine renewable energy’s potential will require a reliable, efficient policy apparatus, as well as the recognition of potential conflicts related to its development and the importance of stakeholder preferences. In this chapter, we examine the state of offshore wind, wave, and tidal energies. Specifically, we analyze each respective technology, its present level of deployment, and projected future growth and costs. We then present insights related to attitudes toward marine renewable energy, focusing on the relevance of technology, people, place, and process. Finally, we appraise the marine renewable energy policy landscape, discussing the relevance of the law of the sea, leasing and zoning, marine spatial planning, and the relationship between marine renewable energy growth and broader energy policies related to decarbonization.