Papa Leo XII (22 Agosti 1760 – 10 Februari 1829) alikuwa Papa kuanzia tarehe 28 Septemba/5 Oktoba 1823 hadi kifo chake. Alitokea Monticelli di Genga, Fabriano, Italia. Jina lake la kuzaliwa lilikuwa Annibale della Genga. Alimfuata Papa Pius VII akafuatwa na Papa Pius VIII. 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 Leo XII katika Kamusi Elezo ya Kikatoliki