Police were called to a property on Ramskir View in the Stainforth area of Doncaster at around 3.05pm on Monday following reports of a disturbance.
On arrival at the scene, officers found a 51-year-old woman who had suffered serious head injuries.
She was taken to hospital where she remains in a life-threatening condition.
Three people – two men aged 47 and 33 and a 24-year-old woman – have been arrested on suspicion of assault.
They remain in custody at this time.
Officers are keen to speak to anyone who witnessed what happened or has any information which may help with their enquiries.
Contact South Yorkshire Police on 101, quoting incident number 539 of May 24, or call Crimestoppers on 0800 555 111.