Symphyotrichum eatonii (formerly Aster eatonii) is a species of aster known by the common name Eaton's aster. It is native to much of western North America from British Columbia to Saskatchewan, the Sierra Nevada in California, the Rocky Mountains region, to Arizona and New Mexico, where it grows in many habitat types, especially wet areas such as meadows and near ditches.
It is a perennial herb growing to a maximum height near one meter from a short rhizome. The leaves are up to 15 centimeters long and lance-shaped and pointed at the tips. Some of the leaves and the upper parts of the stem are hairy.
The inflorescence holds several flower heads containing many white to light violet ray florets around a center of long yellow disc florets. The fruit is a hairy achene.