In this chapter, installation of offshore wind farms is discussed briefly. The installation of offshore wind farms is discussed in four categories corresponding to four main wind farm elements, which are foundations, turbines, substations and cables. For the installation of each category, specialised equipment, vessels and installation methods are necessary. Furthermore, preinstallation activities, such as onshore assembly and offshore transportation, and post-installation activities, such as tests and commissioning are discussed. Precommissioning tests are mandatory to demonstrate proper functionality of turbines and the wind farm as a whole. If all tests are successful, the wind farm can be commissioned and be connected to a grid. In the last section of this chapter, a conclusion is given and innovative offshore installation solutions are described.