Marine spatial planning (MSP) offers an operational framework to address sustainable and well-planned use of ocean space. Spatial allocation has traditionally been single-sector, which fails to account for multiple pressures on the marine environment and user conflicts. There is a need for integrated assessments of ocean space to advance quantitative tools and decision-making. Using the example of offshore wind energy, this article offers thoughts about how MSP has evolved in the United States and how the varying scales of MSP achieve different outcomes. Finally, a review of quantitative and qualitative studies that are needed to support MSP are presented.