Antioxidants are leading the way in the prevention of more than 100 diseases. They are divided into synthetic and natural antioxidants. Due to the harmful effects of synthetic antioxidants, studies on natural antioxidants have intensified. Propolis, which has the highest antioxidant properties among bee products, is a source of natural antioxidants. Propolis shows much stronger antioxidant properties than many medicinal aromatic plants and other bee products. Therefore, in this chapter, the antioxidant potential of propolis, which is a natural and powerful antioxidant, is presented with current in vitro studies.