Yerba mate (from Spanish [ˈʝeɾβa ˈmate]; Portuguese: erva-mate [ˈɛɾvɐ ˈmate] or [ˈɛɾvɐ ˈmatʃɪ]; Guarani: ka'a, IPA: [kaʔa] ) is a species of the holly family (Aquifoliaceae), with the botanical name Ilex paraguariensis A. St.-Hil. named by the French botanist Auguste François César Prouvençal de Saint-Hilaire.

Yerba mate is widely known as the source of the beverage called mate in both Spanish and Portuguese, also called various other names in Portuguese like chimarrão, and tererê/tereré. It is traditionally consumed in central and southern regions of South America, primarily in Paraguay, as well as in Argentina, Uruguay, southern and central-western Brazil, the Chaco region of Bolivia and southern Chile. It is also very popular among the Druze community in Syria and Lebanon, where it is imported from Argentina. Yerba mate was initially utilized and cultivated by the Guaraní people and in some Tupí communities in southern Brazil, prior to European colonization. Yerba mate can also be found in various energy drinks on the market today.

Yerba mate translates to "mate herb", where mate is originally from the Quechua mati, a word that means "container for a drink", "infusion of an herb", as well as "gourd". In English, "mate" is occasionally written "maté", to distinguish it from other meanings of the word mate, although this spelling is not used in Spanish nor Portuguese.