The study evaluated the effects of Chlorella vulgaris, Nannochloropsis salina, and Arthrospira platensis extracts as bio-stimulants on the growth, yield, and antioxidant capacity of common bean plants. The experiments were conducted at Helwan University in Egypt during the 2022 season, using foliar sprays at concentrations ranging from 0.25 to 2.0%. The results showed that N. salina had the highest content of gibberellins (GA3) and auxins (IAA), which are important for plant growth. Application of these extracts at up to 1.0% significantly improved growth parameters such as root and shoot length, number of leaves and flowers, leaf area, and total fresh and dry weight. These extracts also positively affected yield attributes, including the number and fresh weight of pods, seed index, seed yield, and per feddan. Additionally, the application of these extracts increased the chlorophyll content index, with the highest values observed at 0.5% N. salina. The extracts also enhanced the capacity of non-enzymatic and enzymatic antioxidants, reducing oxidative stress markers such as malondialdehyde, electrolyte leakage, and hydrogen peroxide. The most promising results were observed with N. salina and C. vulgaris at 0.5% concentration. The application of these microalgae extracts also improved the quality parameters, proximate composition, seed energy, and mineral contents of the harvested seeds. The study concluded that the use of these extracts up to 1.0% as bio-stimulants can successfully enhance common bean yields and improve the nutritional quality of dried beans. Common beans are a significant source of nutrition, providing complex carbohydrates, dietary fiber, and phyto-compounds with health benefits. Despite their importance, common beans have low yields and may struggle to meet food demands. Bio-stimulants like microalgae extracts offer a promising alternative to chemical inputs, enhancing crop growth, yield, and quality with less environmental damage. The study highlights the potential of these microalgae as effective bio-stimulants for improving common bean cultivation.The study evaluated the effects of Chlorella vulgaris, Nannochloropsis salina, and Arthrospira platensis extracts as bio-stimulants on the growth, yield, and antioxidant capacity of common bean plants. The experiments were conducted at Helwan University in Egypt during the 2022 season, using foliar sprays at concentrations ranging from 0.25 to 2.0%. The results showed that N. salina had the highest content of gibberellins (GA3) and auxins (IAA), which are important for plant growth. Application of these extracts at up to 1.0% significantly improved growth parameters such as root and shoot length, number of leaves and flowers, leaf area, and total fresh and dry weight. These extracts also positively affected yield attributes, including the number and fresh weight of pods, seed index, seed yield, and per feddan. Additionally, the application of these extracts increased the chlorophyll content index, with the highest values observed at 0.5% N. salina. The extracts also enhanced the capacity of non-enzymatic and enzymatic antioxidants, reducing oxidative stress markers such as malondialdehyde, electrolyte leakage, and hydrogen peroxide. The most promising results were observed with N. salina and C. vulgaris at 0.5% concentration. The application of these microalgae extracts also improved the quality parameters, proximate composition, seed energy, and mineral contents of the harvested seeds. The study concluded that the use of these extracts up to 1.0% as bio-stimulants can successfully enhance common bean yields and improve the nutritional quality of dried beans. Common beans are a significant source of nutrition, providing complex carbohydrates, dietary fiber, and phyto-compounds with health benefits. Despite their importance, common beans have low yields and may struggle to meet food demands. Bio-stimulants like microalgae extracts offer a promising alternative to chemical inputs, enhancing crop growth, yield, and quality with less environmental damage. The study highlights the potential of these microalgae as effective bio-stimulants for improving common bean cultivation.