Interior decoration or décor is the art of decorating a room so that it is attractive, easy to use, and functions well with the existing architecture. The goal of interior decoration is to provide a certain "feel" for the room; it encompasses applying wallpaper, painting walls and other surfaces, choosing furniture and fittings, such as light fixtures, and providing other decorations for the area such as paintings, sculptures and rugs.

Interior decorating is done professionally by interior decorators. It is considered a design field.

There is a distinct difference between interior decorating and interior design. Interior decorating is generally focused on finishes, such as wallpaper, paint, window coverings, and furnishings. Interior design, on the other hand, involves manipulating the architectural integrity of the interior space as well as the creation of a lifestyle experience through the study of environmental psychology or human behavior.