Herbal teas or herb teas, technically known as herbal infusions, and less commonly called tisanes, are beverages made from the infusion or decoction of any herbs, spices, or other plant material in water that is not derived from the tea plant (Camellia sinensis). Many herbs used in teas/tisanes are also used in herbal medicine and in folk medicine. Herbal teas are not technically teas because they are not brewed from the tea plant.

The term "herbal tea" is often used to distinguish these infusions from true teas (e.g., black, green, white, yellow, oolong), which are prepared from the tea plant (Camellia sinensis) or, more rarely, its close relatives (such as Camellia taliensis). Beverages actually created from tea and combined with material from other plants are known as "blended teas", "scented teas", or "flavored teas". Examples include jasmine tea, genmaicha, and Earl Grey tea. Unlike true teas, most tisanes do not naturally contain caffeine (though tea can be decaffeinated, i.e., processed to remove caffeine).

A number of plants, however, do contain psychoactive compounds, such as caffeine or another stimulant, like theobromine, cocaine or ephedrine. Some have the opposite effect, acting as a sedative. Some common infusions have specific names such as mate (yerba mate) and rooibos (red bush).

Dictionaries commonly record that the word tea is used to refer to other plants beside the tea plant and to beverages made from these other plants. The term herbal tea is well established and more common than tisane for this usage

Furthermore, in the Etymology of tea, the most ancient term for tea was 荼 (pronounced tu) which originally referred to various plants such as sow thistle, chicory, or smartweed, and was later used to exclusively refer to Camellia sinensis (true "tea").

The word tisane was rare in its modern sense before the 20th century, when it was borrowed in the modern sense from French. This is why some people feel it should be pronounced /tɪˈzɑːn/ as in French, but the original English pronunciation /tɪˈzæn/ continues to be more common in US English and especially in UK English.

The word had already existed in late Middle English in the sense of "medicinal drink" and had already been borrowed from French (Old French). The Old French word came from the Latin word ptisana, which came from the Ancient Greek word πτισάνη (ptisánē), which meant "peeled" barley, in other words pearl barley, and a drink made from this that is similar to modern barley water.

Herbal teas can be made with any part of a plant, including fresh or dried flowers, fruit, leaves, stems, seeds, or roots. These parts may be steeped fully raw (as picked) or processed in some way (such as drying, roasting, crushing, tearing/cutting, steaming, etc.).