Globally, the deployment of offshore wind is expanding rapidly. An improved understanding of the economic, social and environmental impacts of this sector, and how they compare with those of other energy systems, is therefore necessary to support energy policy and planning decisions. The ecosystem services approach provides a more holistic perspective of socio-ecological systems than traditional environmental impact assessment. The approach also makes possible comparisons across disparate ecological communities because it considers the societal implications of ecological impacts rather than remaining focused on specific species or habitats. By reporting outcomes in societal terms, the approach also facilitates communication with decision makers and the evaluation of trade-offs. The impacts of offshore wind development on ecosystem services were assessed through a qualitative process of mapping the ecological and cultural parameters evaluated in 78 empirical studies onto the Common International Classification for Ecosystem Services (CICES) framework. The research demonstrates that a wide range of biophysical variables can be consistently mapped onto the CICES hierarchy, supporting development of the ecosystem service approach from a broad concept into an operational tool for impact assessment. However, to improve confidence in the outcomes, there remains a need for direct measurement of the impacts of offshore wind farms on ecosystem services and for standardised definitions of the assumptions made in linking ecological and cultural change to ecosystem service impacts. The process showed that offshore wind farms have mixed impacts across different ecosystem services, with negative effects on the seascape and the spread of non-native species, and positive effects on commercial fish and shellfish, potentially of most significance. The work also highlighted the need for a better understanding of long term and population level effects of offshore wind farms on species and habitats, and how these are placed in the context of other pressures on the marine environment.