Luzha River (Russian: Лужа) is a river in Kaluga Oblast in Russia, which originates in Moscow Oblast. It is a right tributary of the Protva River (Oka's basin). The length of the river is 159 km (99 mi). The area of its drainage basin is 1,400 km² (540 sq mi). The Luzha freezes up in November (rarely in December) and breaks up in April.