Lauenburg, or Lauenburg an der Elbe, is a town in the state of Schleswig-Holstein, Germany. It is situated on the northern bank of the river Elbe, east of Hamburg. It is the southernmost town of Schleswig-Holstein and belongs to the Kreis (district) of Herzogtum Lauenburg. Lauenburg had a recorded population on 31 December 2013 of 11,253.

Lauenburg is a notable old town with a number of historic buildings from the 17th century and earlier. In the past these houses were mostly the homes of sailors. Today, the area appeals to artists as well as tourists. Furthermore, the Maria-Magdalenen Church, built in the 13th century is another attraction of the old town of Lauenburg.

The old town is nestled at the bottom of about 50 meter high bluffs. The picturesque narrow streets up the hill lead to the so-called "upper town" where Lauenburg Castle is located. The old Lauenburg Castle used to be the residence of the Dukes of Lauenburg and the political centre of the Dukedom. Over the century most parts were destroyed and replaced by modern buildings. Though, the old castle tower remains till today. Nowadays, the castles serves as city and municipal administration. A walk up to the castle is worth the effort though, because of the view.

One cannot only see the beautiful river Elbe and the old town of Lauenburg, but also the flat marshland of Lower-Saxony on the southern shore of the Elbe, which used to belong to the duchy until it was ceded to the then neighbouring Kingdom of Hanover in 1814. On a clear day it is possible to see as far as Lüneburg, about 25 km (16 mi) southwest of Lauenburg. Another historic sight of Lauenburg is the "Palmschleuse", a historic river lock, originally built in 1398 and renewed in the 17th century. It is the oldest such lock in Europe.