Willisau is a municipality located in the district of Willisau within the canton of Lucerne, Switzerland. The current administrative boundaries were established on January 1, 2006, following the merger of the former municipalities of Willisau Land and Willisau Stadt.
The municipality further expanded on January 1, 2021, when it incorporated the former municipality of Gettnau. It serves as a central location within its namesake district in the Lucerne region.