Seaweed liquid extracts are used as nutrient supplements, biostimulants and biofertilizers as an alternative to chemical fertilizers in agriculture. The study was set up to evaluate the biofertilizing efficiency of seaweed liquid  extracts (SLE) of green and red marine algea (Ulva flexusoa, Enteromorpha intestinalis and Griffithsia teges) on growth, biochemical and yield of Hot Pepper .To achieve the objectives, Seaweed liquid extracts at concentration 2.0% were prepared and applied as foliar spray on Hot Pepper seedlings raised in experimental pots maintained under natural conditions.After 30 and 70 days, the growth and biochemical parameters and yield attributes were measured , respectively. The results exhibited that the extracts of Ulva flexusoa and  Enteromorpha intestinalis  more efficient than Griffithsia teges ( shoot and root length, total fresh and dry weight, leaf area , the photosynthetic pigments , and  phytohormone analysis) . The  auxins in the (Ulva flexusoa, Enteromorpha intestinalis and Griffithsia teges (7.41 mg/ml, 10.6 mg/ml  and 11.58 mg/ml) respectively and gibberelines were (15.00 mg/ml, 15.22 mg/ml and 7.26 mg/ml) respectively. Thus, Ulva flexusoa and  Enteromorpha intestinalis liquid extract could serve as an promising effective organic biostimulant to replace the chemical fertilizers for sustainable agriculture .