Guardiola diehlii is a very rare (quite possibly extinct) North American species of plants in the family Asteraceae, found only in the state of New Mexico in the southwestern United States.

[2] Guardiola diehlii is (was) an annual herb measuring up to 30 cm (1 ft) tall.

One plant will produce several flower heads in a flat-topped array.

Each head contains only one white ray flower and 4 disc flowers.

This Millerieae article is a stub.