The Betoideae are a small subfamily of the flowering plant amaranth family, Amaranthaceae sensu lato. Commonly known members include beet, sugar beet, chard, and mangelwurzel, which all are cultivars of Beta vulgaris.

Amaranthaceae is a family of flowering plants commonly known as the amaranth family, in reference to its type genus Amaranthus. It includes the former goosefoot family Chenopodiaceae and contains about 165 genera and 2,040 species, making it the most species-rich lineage within its parent order, Caryophyllales.