Papa Stefano IX, O.S.B. (takriban 1020 – 29 Machi 1058) alikuwa Papa kuanzia tarehe 2/3 Agosti 1057 hadi kifo chake. Alitokea Lorraine, leo nchini Ufaransa. Jina lake la kuzaliwa lilikuwa Frederic de Lorraine. Alimfuata Papa Vikta II akafuatwa na Papa Nikolasi II. Orodha ya Mapapa 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 Papa Stefano IX katika Kamusi Elezo ya Kikatoliki