蒙德古河 （Mondego，IPA：[mõ'ðeɣu]）是完全在葡萄牙最长的河流，长234公里。发源于埃什特雷拉山脉，先往东，再转往西经科英布拉，最后在菲盖拉-达福什以南流入大西洋。

The Rio Mondego (Portuguese pronunciation: [mõˈdeɡu]; English language: Mondego River) is the longest river located exclusively in Portuguese territory. It has its source in Serra da Estrela, the highest mountain range in mainland Portugal (i.e. except the Portuguese islands). It runs 234 kilometres (145 mi) from the Gouveia municipality, at 1,425 metres (4,675 ft) above sea level in Serra da Estrela, to its mouth in the Atlantic Ocean next to the city of Figueira da Foz.