A detailed study of the present global energy landscape reveals the urgent need to shift towards renewable energy sources. Among the various renewable sources, bioenergy, particularly derived from algal biomass, is emphasized as a promising alternative. The chapter discusses the challenges associated with bioenergy production using first- and second-generation feedstocks, highlighting the benefits of algal biomass as a third-generation feedstock with numerous advantages, including rapid growth, CO2 sequestration, and versatile applications. Commonly used open and closed algal cultivation systems, including open raceways and closed photobioreactors, have been explained in detail. The wastewater treatment efficiency of different algal strains has been discussed in detail. The chapter further explains the biochemical, chemical, and thermochemical conversion of algal biomass into biofuels. The concept of algal biorefinery is introduced, emphasizing its potential to yield a wide range of value-added products, including biofuels, pharmaceuticals, sustainable lubricants, nutraceuticals, and animal feed. The chapter concludes by emphasizing the need for more research and development to optimize algal cultivation and biorefinery processes, thereby unlocking the full potential of this sustainable resource for a greener and more sustainable future.