Industrial activities, especially those in the food sector, demand large volumes of water and generate wastewater laden with organic compounds, nutrients, and heavy metals. When these wastewaters are improperly discharged, eutrophication spreads, potentially pathogenic microorganisms proliferate, and the delicate balance of aquatic ecosystems is irreversibly compromised. Conventional wastewater treatment systems, despite being costly and requiring large amounts of energy, are often not capable of completely removing pollutants. Therefore, there is an urgent need for changes in the relationship between industrial production and water resources, aiming to adopt environmentally friendly technologies. In contrast, promising alternatives are emerging, such as microalgae, which not only contribute to wastewater recovery but also accumulate biomass, a resource with added value. Microalgal biomass, in turn, can be used as raw material for the extraction of bioactive compounds and production of biofuels, animal feed, and biofertilizers. Currently, there are two main systems for microalgae cultivation: open systems (raceways) and closed systems (photobioreactors). Both systems require precise control of specific environmental conditions for cultivation, such as light, temperature, pH, and nutrients. In this context, the main objective of this chapter is to present the use of industrial wastewater as a nutritional source for the sustainable cultivation of microalgae. This chapter will address the use of food industry wastewater as an alternative nutritional source for microalgae, exploring cultivation systems, nutrient absorption, and conversion mechanisms. Furthermore, it will discuss the environmental impacts and the factors that influence the efficiency of this process.