A lunch box, spelled lunchbox in almost all UK and US dictionaries,[1] also referred to as a lunch pail or lunch kit, is used to store food to be taken anywhere. The concept of a food container has existed for a long time, but it was not until people began using tobacco tins to carry meals in the early 20th century, followed by the use of lithographed images on metal, that the containers became a staple of youth, and a marketable product.

The lunch box has most often been used by schoolchildren to take packed lunches, or a snack, from home to school. The most common modern form is a small case with a clasp and handle, often printed with a colorful image that can either be generic or based on children's television shows or films. Use of lithographed metal to produce lunch boxes in the 1950s, 1960s, 1970s and 1980s gave way in the 1990s to use of injection-molded plastic.

A lunch kit comprises the actual "box" and a matching vacuum bottle. However, pop culture has more often embraced the singular term lunch box, which is now most commonly used.