While microalgae biotechnology already supports the production of food and pharmaceuticals, its commercial applications remain limited by costs and difficulty to scale. Among various challenges, harvesting can account for up to 30% of the total production costs because microalgae cultures typically contain less than 0.5 g of dry biomass per liter of cultivation broth, meaning that significant volumes of water must be removed relative to the amount of biomass recovered. Consequently, microalgae harvesting typically requires the use of several processes in series to deliver cost-efficiency, and each step must be selected and/or developed depending on the biomass characteristics and other key process parameters. This chapter presents and discusses the suitability of established and emerging microalgae biomass harvesting technologies in light of their technical feasibility, economics, and sustainability.