Logar River (also Lowgar) is a river of Afghanistan. It gives the name to the Logar Valley and Logar Province.
The Logar River drains a wide tract of country, rising in the southern slopes of the Sanglakh Range and receiving tributaries from the Kharwar hills, north-east of Ghazni. It joins the Kabul River a few miles below the city of Kabul. The fertile and well irrigated Logar Valley, which is watered by its southern tributaries, is about 64 km (40 mi) long by 19 km (12 mi) wide. Lying in the vicinity of the capital, the district contributes significantly to its food supply.