Papa Pius III (29 Mei 1439 – 18 Oktoba 1503) alikuwa Papa kwa siku chache kuanzia tarehe 22 Septemba/1/8 Oktoba 1503 hadi kifo chake. Alitokea Siena, Italia. Jina lake la kuzaliwa lilikuwa Francesco Todeschini Piccolomini. Alimfuata Papa Aleksanda VI akafuatwa na Papa Julius II. Orodha ya Mapapa Papa Pius III katika Kamusi Elezo ya Kikatoliki https://www.vatican.va/content/vatican/en/holy-father.index.html#holy-father https://www.vatican.va/content/vatican/en/holy-father.index.html#holy-father