Algae have emerged as one of the most versatile and sustainable natural resources offering solutions to critical global challenges in agriculture environmental conservation food security and industrial innovation. Their ability to grow rapidly in diverse environments while requiring minimal resources makes algae a key player in advancing sustainability. This book Algae in Agriculture and Environmental Innovation provides a comprehensive understanding of the significant roles algae can play in shaping a sustainable future serving as an essential resource for researchers students and professionals alike. In agriculture algae provide eco-friendly alternatives to synthetic inputs that often harm soil health and the environment. Algal biomass serves as a sustainable fertilizer enriching the soil with essential nutrients and promoting microbial activity. Unlike chemical fertilizers algae-based fertilizers improve long-term soil health reducing erosion and increasing crop productivity. Additionally algae act as biostimulants enhancing plant growth stress tolerance and nutrient uptake.