Undalya (Postcode: 5451) is a small rural town on the southern edge of the Clare Valley, in the mid north of the state of South Australia.

It is located on the Horrocks Highway approximately halfway between the towns of Auburn and Rhynie, at the junction of the River Wakefield and Pine Creek.

On one of his expeditions, explorer Edward John Eyre camped at Undalya and commented on the large amount of water in the River Wakefield as well as the availability of the local blue limestone.

In 1866, with a grant of money and land from another local farmer, the Roman Catholic Church of St. Patrick was built by the Jesuit Fathers of Sevenhill on the hill just south of the village.

People buried there include Patrick Michael Ryan, who discovered copper at Tiparra in 1861, which was the start of the famous Moonta mine, and the first wife of the father of Auburn poet C.J.

One such example is that of George Henry Michell, who moved his family to Undalya in 1870, after living at Cudlee Creek, where he had acquired the art of wool-scouring.