Wallpaper is a kind of material used to cover and decorate the interior walls of homes, offices, cafes, government buildings, museums, post offices, and other buildings; it is one aspect of interior decoration.

It is usually sold in rolls and is put onto a wall using wallpaper paste.

Wallpapers can come plain as "lining paper" (so that it can be painted or used to help cover uneven surfaces and minor wall defects thus giving a better surface), textured (such as Anaglypta), with a regular repeating pattern design, or, much less commonly today, with a single non-repeating large design carried over a set of sheets.

Wallpaper printing techniques include surface printing, gravure printing, silk screen-printing, rotary printing, and digital printing. Wallpaper is made in long rolls, which are hung vertically on a wall.