The field experiment was carried out to determine the effect of planting time and fruit maturity stage of antioxidant activity. The results show that the fruit maturity stage and planting time significantly (P<0.005) influenced the antioxidant activity in sweet pepper. Each planting time presented significant differences in antioxidant compounds depending on the maturity stage, but we could recommend 2nd week of May as the optimal planting time if fruits are to be harvested for greater antioxidant activity for CUPRAC, phenols and anthocyanin, while FRAP contents were recorded second highest during this period. From the nutritional point of view, the red state was the most appropriate state of maturation, since red peppers had the highest levels CUPRAC, FRAP and anthocyanin. The concentration of these phytochemicals except total phenolic contents increased as the peppers reached at mature red stage. These results will definitely be prove useful to sweet pepper growers, especially in their selection of planting time and stage of fruit maturity with high antioxidant activity so as to meet the increasing consumer demand for healthy food.