It happened on Findlay Avenue in the Bronx.
A 12-year-old girl was hosting the sleepover, and there was an adult home at the time of the incident.
The 11-year-old victim fell asleep on a couch, then at 4 a.m. she awoke to the 12-year-old girl allegedly pouring the boiling water on her.
She was taken to Harlem Hospital with serious burns. She's currently in stable condition.
The 12-year-old girl is being charged as a juvenile, and the case will be handled in family court.