Green tomatoes are unripe tomatoes (Solanum lycopersicum), picked before they redden and sweeten, which gives them a firm texture and a tart, tangy flavor in place of a ripe tomato's sweetness. Tomatoes originated in South America and were domesticated by Indigenous peoples of Mesoamerica before Spanish colonization introduced them to Europe in the 16th century.
Green tomatoes have a particular hold in Southern U.S. cooking, most famously fried, but they're also pickled or worked into relishes, chutneys, and salsas; their firm texture holds up in soups, stews, and casseroles, and their acidity can balance sweetness in pies and tarts.
They pair well with vinegar, lemon, or lime juice; herbs like thyme and basil; and richer partners like bacon, ham, or fried breading that offset their tartness.