Macroalgae are a relatively novel and untapped source of biologically active compounds (i.e., polysaccharides, proteins-peptides, lipids, polyphenols, and carotenoids) with promising applications in the food industry. The industrial utilization of high-value compounds as an alternative to traditional products requires the development of green, efficient, and sustainable extraction protocols. Microwave-assisted extraction (MAE) is currently one of the most promising technologies to generate high yields of bioactive compounds from macroalgae, while reducing the production of waste, use of organic solvents, and energy consumed during the extraction process. This chapter summarizes the principles of microwave technologies together with the technological equipment currently available at industrial level. The recent MAE protocols to extract high-value compounds from macroalgae will also be discussed together with other uses of MAE in analytical chemistry and the future trends and industrial applications of microwave technologies in the macroalgal sector.