The United Kingdom is a European and world leader for installed offshore wind energy capacity. Despite its benefits, offshore wind energy may have a range of negative environmental impacts. This article will examine and critically assess the regime for environmental assessment and approval of offshore wind energy projects in England and Wales. It will begin by giving an overview of the broader framework for the location and selection of sites for offshore wind energy facilities, including the role of Strategic Environmental Assessment, the establishment of zones for development, procedures for obtaining tenure over the sea bed, and non-mandatory procedures for environmental assessment at the zone level. The article will then describe and critically analyse the environmental assessment and approval procedures for individual offshore wind energy projects that classify as national infrastructure projects under the Planning Act 2008 (UK). While the government's 2011 National Policy Statements for Energy have been crucial to achieving a high rate of success of applications for development consent, concerns remain in relation to the assessment of offshore wind energy projects, in particular the cumulative impacts on birds and marine mammals, and the most appropriate methodologies for predicting and measuring these impacts.