Zucchini (Zoo-Keen-Ee) (US, Australian, and Canadian English) or courgette (New Zealand and British English) is a small summer marrow or squash, also commonly called Italian squash. Its Latin name is Cucurbita pepo (a species which also includes other squash). It can either be yellow or green and generally has a similar shape to a ridged cucumber, though a few cultivars are available that produce round or bottle-shaped vegetable. Unlike the cucumber it is usually served cooked, often steamed or grilled. Its flower can be eaten fried or stuffed. Culinarily, zucchini is considered to be a vegetable. However, biologically, the zucchini is a fruit, being the swollen ovary of the zucchini flower. Zucchini are traditionally picked when very immature, seldom over 8in/20cm in length. Mature zucchini can be as much as three feet long, but are often fibrous and not appetizing to eat.

Zucchini is one of the easiest vegetables to cultivate in a temperate climate. As such, zucchini has a reputation among home gardeners for overwhelming production, and a common type of joke among home growers revolves around creative ways of giving away unwanted zucchini to people who already have been given more than they can use.

In 2005, a poll of 2,000 people revealed the courgette to be Britain's 10th favourite culinary vegetable. In Mexico, the flower (known as Flor de Calabaza) is preferred over the vegetable, and is often cooked in soups or used as a filling for quesadillas.

Closely related, to the point where some seed catalogs do not make a distinction, are Lebanese summer squash or kusa, which closely resemble zucchini but often have a lighter green or even white color.