A paintbrush is a brush used to apply paint or ink. A paintbrush is usually made by clamping bristles to a handle with a ferrule. They are available in various sizes, shapes, and materials. Thicker ones are used for filling in, and thinner ones are used for details. They may be subdivided into decorators' brushes used for painting and decorating and artists' brushes used for visual art.

Paintbrushes were used by humans as early as the Paleolithic era around 2.5 million years ago in order to apply pigment.

Old painting kits, estimated to be around 100,000 years old, were discovered in a cave in what is now modern South Africa.

Ancient Egyptian paintbrushes were made of split palm leaves and used by ancestors to beautify their surroundings. The oldest brushes ever found were also made of animal hair.

A paintbrush consists of three main components: the bristles, the ferrule, and the handle. The bristles, which form the tuft of the brush, are responsible for transferring paint onto the surface being painted. They may be made from natural or synthetic materials, depending on the intended application. The ferrule is the metal band that holds the bristles in place and secures them to the handle. The handle serves as the interface between the user and the tool.

Brushes for use in non-artistic trade painting are geared to applying an even coat of paint to relatively large areas. Following are the globally recognized handles of trade painter's brushes:

The sizes of brushes used for painting and decorating.

Decorators' brush sizes are given in millimeters (mm) or inches (in), which refers to the width of the head. Common sizes are: