A bento (弁当, bentō) is the Japanese iteration of a single-portion take-out or home-packed meal, often for lunch. Outside Japan, it is common in other East and Southeast Asian culinary styles, especially within Chinese, Korean, Singaporean, Taiwanese cuisines and more, as rice is a common staple food in the region. The term bento is derived from the Chinese term biandang (便當, pinyin: biàndāng), which means "convenient" or "convenience".

A traditional bento may contain rice or noodles with fish or meat, often with pickled and cooked vegetables in a box. Containers range from mass-produced disposables to hand-crafted lacquerware. Often various dividers are used to separate ingredients or dishes, especially those with strong flavors, to avoid them affecting the taste of the rest of the meal. A typical divider is green plastic grass, also known as the 'sushi grass'. This also works to slow the growth of bacteria.

Bento are readily available in many places throughout Japan, including convenience stores, bento shops (弁当屋, bentō-ya), railway stations, and department stores. However, Japanese homemakers often spend time and energy on carefully prepared box lunches for their spouses, children, or themselves. Outside Japan, the term bento box may be used (e.g., on English menus for Japanese restaurants). Bentos can be elaborately arranged in a style called "kyaraben" ("character bento"), which are typically decorated to look like popular characters from Japanese animation (anime), comic books (manga), or video games. Another popular bento style is "oekakiben" or "picture bento". This is decorated to look like people, animals, buildings and monuments or items such as flowers and plants. Contests are often held where bento arrangers compete for the most aesthetically attractive arrangements.

There are comparable forms of boxed lunches in other Asian countries such as in China, Taiwan and other Sinophone communities as biàndāng in Mandarin and piān-tong in Taiwanese Hokkien or in Korea as dosirak (Hangul: 도시락; Hanja: 道食樂). Other Asian countries would either just use bento as a loanword or hokben, which means steaming bento. There has also been discussion regarding what the bento means for Japanese society and what it represents. The analyses range from a simple semiotic approach to one that outlines the deeper ideological meanings behind the bento.