Domhnall Mac Domhnaill (died 1318?), also known as Domhnall of Islay and Domhnall of the Isles, was a fourteenth-century Scottish nobleman. He appears to have been a member of Clann Domhnaill. First attested in the first decade of the fourteenth century, Domhnall appears to be last recorded in the second decade upon his death. Domhnall's attestations suggest that he was a claimant to the chiefship of Clann Domhnaill, and may have possessed the chiefship.