Zanthoxylum is a genus of about 250 species of deciduous and evergreen trees, shrubs and climbers in the family Rutaceae that are native to warm temperate and subtropical areas worldwide. It is the type genus of the tribe Zanthoxyleae in the subfamily Rutoideae. Several of the species have yellow heartwood, to which their generic name alludes. Several species are cultivated for their use as spices, notably including Sichuan pepper.

Plants in the genus Zanthoxylum are typically dioecious shrubs, trees or woody climbers armed with trichomes. The leaves are arranged alternately and are usually pinnate or trifoliate. The flowers are usually arranged in panicles and usually function as male or female flowers with four sepals and four petals, the sepals remaining attached to the fruit. Male flowers have four stamens opposite the sepals. Female flowers have up to five, more or less free carpels with the styles free or sometimes fused near the tip. The fruit is usually of up to four follicles fused at the base, each containing a single seed almost as large as the follicle.

The genus Zanthoxylum was first formally described in 1753 by Carl Linnaeus in the first volume of Species Plantarum. The generic name is derived from Ancient Greek words ξανθός (xanthos), meaning 'yellow', and ξύλον (xylon), meaning 'wood'. It is technically misspelled, as the z should be x, but botanical nomenclature does not allow for spelling corrections. It refers to a yellow dye made from the roots of some species. The first species that Linnaeus described was Zanthoxylum trifoliatum, now regarded as a synonym of Eleutherococcus trifoliatus. The once separate genus Fagara is now included in Zanthoxylum.

28 fossil seeds of the extinct Zanthoxylum kristinae, from the early Miocene, have been found in the Kristina Mine at Hrádek nad Nisou in North Bohemia, the Czech Republic.

Many Zanthoxylum species make excellent bonsai and in temperate climates they can be grown quite well indoors. Zanthoxylum beecheyanum and Zanthoxylum piperitum are two species commonly grown as bonsai.

Spices are made from a number of species in this genus, including:

In Indonesia's North Sumatra province, Zanthoxylum acanthopodium is harvested for andaliman. In Indonesian Batak cuisine, andaliman is ground and mixed with chilies and seasonings into a green sambal or chili paste. Arsik is a typical Indonesian dish containing andaliman.

Zanthoxylum piperitum is harvested in Japan and Korea to produce sanshō (山椒) or chopi (초피), which has numbing properties similar to those of Chinese Sichuan peppercorns. In Korean cuisine, chopi is often used to accompany fish soups such as chueo-tang, whereas the plant's seeds are separated and used to make oil, and the oil is used as a medicine.