Xanthoparmelia isidiovagans is a species of foliose lichen in the family Parmeliaceae
The yellowish-green thallus of Xanthoparmelia isidiovagans reaches a diameter of 2–, comprising elongated, linear lobes measuring 1– wide. It contains several secondary compounds, including stictic acid as a major metabolite, usnic acid, norstictic acid, constictic acid, and cryptostictic acid as minor metabolites, and trace amounts of peristictic acid.
Found in Spain, it was formally described as a new species in 2005 by lichenologists Oscar Blanco, Ana Crespo, Pradeep Divakar, and John Elix. The type specimen was collected in Torremocha del Pinar (Guadalajara) at an elevation of 1200m (3,900feet). Here the lichen was found growing as a vagrant on the soil in open forest dominated by Juniperus thurifera and . The specific epithet isidiovagans alludes to its resemblance to the American species Xanthoparmelia vagans, from which it differs by the presence of isidia.