The Logar (also Lowgar) is a river and valley of Afghanistan. The Logar river drains a wide tract of country, rising in the southern slopes of the Sanglakh range and receiving affluents 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 affluents, is about 40 miles long by 12 miles wide. Lying in the vicinity of the capital, the district contributes largely to its food-supply.

The valley was traversed in 1879 by a brigade under Field Marshal Sir Frederick Sleigh Roberts.