There is an increasing demand for energy in the world. It is well known that non-renewable energy reserves will be irreversibly used at some point. The effects of climate change and limited fossil energy resources have led to an increasing interest in generating energy such as electricity from renewable energy resources. Wind energy is currently the most important renewable energy source for electricity generation which is rapidly becoming a key objective of most European and other countries due to a high demand, both economically and politically. Wind energy provides a safe, clean, sustainable and competitive alternative for conventional sources of energy. European countries like Germany, the Netherlands, United Kingdom, Denmark and Sweden are currently operating offshore wind farms (OWFs) and have plans to increase the production of electricity by wind power. The growth of OWFs has raised concerns about their impact on the marine environment. Focus of this review is to show possible impacts of OWFs on the physical and biological environment reviewing existing knowledge from the literature.