Landau an der Isar (Central Bavarian: Landa an da Isar) is the second-largest town in the Lower Bavarian district, or Landkreis, of Dingolfing-Landau, in the state of Bavaria, Germany.

The town had been a Pflegamt for many years and belonged to the Landshut Rentamt [bar; de; es] of the Electorate-Principality (Kurfürstentum) of Bavaria.

Landau possessed a town court with broad magisterial powers (Landgericht).

Until the Bavarian county reform, or Kreisreform in German, in 1972, Landau was the district seat (Kreisstadt) of its own Landkreis, having the license plate code LAN.

The town is bound by the Bundesstraße 20 and the Bundesautobahn 92 and lies on the train line Landshut–Wörth a.d.Isar–Dingolfing–Landau a.d.Isar–Wallersdorf–Plattling.