The Wigger (formerly also called Wiggeren)[1] is a river in the Swiss cantons of Lucerne and Aargau.

Shortly after the small city of Willisau it joins with the Buchwigger and is called just Wigger from there.

North of Dagmersellen the Wigger is mostly restricted to a canal bed and flows partially parallel to the A2 motorway.

In 1821 the Wigger's course was corrected (channelized) by order of the government of the canton of Aargau.

Until the second half of the 19th century the area of the Wigger's confluence with the Aar was a location of placer mining for gold, but this stopped due to dissatisfactory yield.