This chapter provides a comprehensive overview of the Life Cycle Assessment (LCA) applied to microalgae-based technologies and products, emphasizing their potential as a sustainable alternative to conventional fossil fuels. Microalgae, recognized for their high efficiency in biomass production and the ability to be cultivated in environments unsuitable for traditional agriculture, offer significant environmental sustainability advantages. The chapter explores the environmental, economic, and social impacts associated with biofuel and bioproduct production and the integration of microalgae in wastewater treatment. It highlights the need for process optimization to maximize energy efficiency and reduce greenhouse gas (GHG) emissions. Furthermore, commonly used LCA methodologies are analyzed, identifying key areas for improvement and standardization to enhance the commercial viability and widespread adoption of microalgae-based technologies. The insights gained from these assessments provide crucial information for strategic decision-making in the transition toward a circular, low-carbon economy, where microalgae play a crucial role in climate change mitigation and global sustainability.