ABSTRACT. The European Union Marine Strategy Framework Directive requires the Good Environmental Status of marine environments in Europe's regional seas; yet, maritime activities, including sources of marine degradation, are diversifying and intensifying in an increasingly globalized world. Marine spatial planning is emerging as a tool for rationalizing competing uses of the marine environment while guarding its quality. A directive guiding the development of such plans by European Union member states is currently being formulated. There is an undeniable need for marine spatial planning. However, we argue that considerable care must be taken with marine spatial planning, as the spatial and temporal scales of maritime activities and of Good Environmental Status may be mismatched. We identify four principles for careful and explicit consideration to align the requirements of the two directives and enable marine spatial planning to support the achievement of Good Environmental Status in Europe's regional seas.Key Words: DPSWR; Good Environmental Status; marine spatial planning; maritime spatial planning; spatial scale temporal scale THE POLICY CONTEXT Global and regional assessments confirm that the capacity of our ocean ecosystems to continue to deliver ecosystem services that underpin human well-being is declining because of human activities (e. The EU is drafting a directive on MSP specifically to give cross-border cooperation a firm legal footing (European Commission 2013). Although the responsibility for MSP lies at the national level and addresses maritime activities in a nation's Exclusive Economic Zone (EEZ), a transnational, subregional, and even a regional sea perspective is called for when maritime activities and/or their effects cross national borders (Gee et al. 2011). This creates considerable challenges for the planning process and stakeholder consultation (e.g., Argardy et al. 2011, Maritime Spatial Planning in the North Sea 2012, Halpern et al. 2012, Jentoft and Knol 2014. However, it also provides challenges for assessing effects on the marine environment given the requirement under the MSFD to achieve GES at subregional and 9]). We address effects on the marine environment by examining the spatial and temporal dimensions of both GES and MSP.We examine the role of MSP in an ecosystem approach and MSP's potential contributions to achieving GES. We aim to assess whether mismatches of spatial and temporal scales between MSP and marine ecosystems might constrain this role and these contributions. The methodology is based on the Driver Pressure State Welfare Response (DPSWR) framework (Cooper 2013). Findings are illustrated by two case studies representing aspects of traditional and emerging sea use. We use DPSWR to provide a context for MSP in an ecosystem approach to achieve GES. We then compare the spatial and temporal scales of MSP and GES. We identify a number of principles that require explicit consideration by MSP. These principles address the specific focus of our work; namely, the spatial an...