Microalgal biorefineries represent a promising frontier in sustainable biofuel production and the generation of value-added bioproducts. This chapter explores the biorefinery concept, emphasizing microalgae’s unique potential as a versatile feedstock due to its high productivity, adaptability, and ability to accumulate different valuable compounds. It highlights microalgal applications in biofuel production, nutraceuticals, biomedicine, and agrochemicals while addressing techno-economic and environmental challenges. Key barriers include high operational costs, low biomass production efficiency, and the energy-intensive nature of cultivation and processing. The chapter discusses advancements in cultivation techniques, harvesting technologies, and bioproduct extraction methods that aim to optimize resource utilization and economic viability. Furthermore, integrating tools like life cycle assessment (LCA) and techno-economic analysis (TEA) is essential for evaluating and improving sustainability metrics. Finally, innovations in zero-waste biorefining and coupling CO2 capture with biofuel production underscore the potential of microalgal biorefineries to contribute significantly to global renewable energy and sustainable development goals.