The use of algae in biofertilizer production is considered one of the emerging approaches supporting sustainable agriculture, as it can contribute to improving nutrient-use efficiency and reducing the need for some chemical inputs when incorporated into an appropriate fertilization program. Among the most prominent agricultural applications of algae is the use of nitrogen-fixing cyanobacteria in certain rice cultivation systems, where they contribute to biological nitrogen fixation and support soil fertility. Algal biomass can also be added to soil as a source of organic matter and nutrients, helping improve certain soil properties. In addition, seaweed extracts are used to stimulate plant growth and enhance tolerance to some environmental stresses. Algae can also be utilized in biological water-treatment systems to recover certain nutrients, provided that the resulting materials are assessed for safety before agricultural application. Despite their potential benefits, the agricultural use of algae faces several challenges, including variations in the effectiveness of different species and strains, the costs of production, harvesting, and processing, and the difficulty of determining optimal application rates for each crop and soil type. It is also essential to ensure that algal products are free from contaminants and potential algal toxins, particularly when they are produced from unmonitored aquatic sources. Therefore, expanding the use of algae in agriculture requires scientifically designed field trials to identify the most suitable species and application methods, as well as to evaluate their effects on soil fertility and agricultural productivity over both the short and long term. In conclusion, algae represent a promising biological resource for advancing sustainable agriculture because of their potential roles in supporting soil fertility, improving certain soil properties, increasing nutrient availability, and promoting plant growth and productivity under suitable conditions. Accordingly, encouraging scientific research into agricultural applications of algae and developing efficient methods for producing algae-based biofertilizers are important steps toward conserving natural resources and achieving more sustainable agricultural production. Al-Mustaqbal University – The First University in Iraq