The 20-year-old was taken to Ibiza's Hospital de Can Misses hospital after the accident where her outlook is uncertain, Catalan daily La Vanguardia reported.
She fell from the fourth floor of a building in Sant Antoni de Portmany, the daily added.
The cause of the accident is not yet known.
"We are aware of the reports of the hospitalisation of a British National in Ibiza on June 12th and are liaising with the local authorities. We stand ready to provide consular assistance," the British Embassy in Madrid told The Local.
The woman is the second Brit to suffer such a fall in the Ibiza town of San Antoni in a week. On Saturday a 30-year-old British man was taken to hospital after falling from a second-floor apartment.
It is not known whether either person was a victim of 'balconing', a dangerous practice which usually involves trying to jump from one balcony to another, or leaping from a balcony into a swimming pool.