Masking tape is a type of adhesive tape made of easy-to-tear paper backed with a relatively weak adhesive. It is used mainly in painting, to mask off areas that shouldn't be painted. The adhesive is the key element to its usefulness, as it allows the tape to be removed without stripping off newly-applied paint. It is available in several strengths, rated on a 1-100 scale based on the aggressiveness of the adhesive. Most painting operations will require a tape in the 50-range.

Masking tape was invented in 1925 by 3M employee Richard Drew. Drew observed auto-body workers growing frustrated when they removed butcher paper they had taped to cars they were painting. The strong adhesive on the tape peeled off some of the paint they had just applied. Touching up the damaged areas increased their costs. Drew realized the need for tape with a more gentle adhesive.

Masking tape has become common for many household uses. Because of this it is an even weaker paper and lower grade adhesive. This is fine for most uses. But for its original use, of marking off areas where auto body paint is not desired, a special grade of painter's masking tape is needed. With this special grade, very clean lines can be produced. Without it, the paint bleeds under the edges of the tape, producing a fuzzy or varied line.