The Oder River (German: Oder; Czech/Polish: Odra) is a river in Central Europe. It starts in the Czech Republic and flows through Poland and Germany. It forms 187 kilometers of the border between Poland and Germany. The river is 854 kilometres long and ends in the Szczecin Lagoon in the Baltic Sea.

Some bigger towns the Oder passes are Wrocław, Eisenhüttenstadt, Frankfurt on the Oder, Szczecin and Police. The biggest city on the Oder River is Wrocław, in Lower Silesia, Poland.