De Wallen (Dutch pronunciation: [də ˈʋɑlə(n)]) or De Walletjes (Dutch pronunciation: [də ˈʋɑləcəs]) is the largest and best known red-light district in Amsterdam. It consists of a network of alleys containing approximately three hundred one-room cabins rented by prostitutes who offer their sexual services from behind a window or glass door, typically illuminated with red lights. These "kamers" are the most visible and typical kind of red light district sex work in Amsterdam and are a large tourist attraction.

De Wallen, together with the prostitution areas Singelgebied and Ruysdaelkade, form the Rosse Buurt (red light areas) of Amsterdam. Of these De Wallen is the oldest and largest area.

The area also has a number of sex shops, sex theatres, peep shows, a sex museum, a cannabis museum, and a number of coffee shops that sell marijuana.