Police were alerted to the murder at Block 852 Woodlands Street 83 at around 2.50am.
The Chinese teenager was pronounced dead by paramedics at the scene at around 3.06am.
A 51-year-old woman, Goh Hai Eng, believed to be the girl's mother and said to be mentally unsound, has been arrested.
She was charged with murder in court on Thursday afternoon.
Neighbours said the girl lived with her mother and a married sister, who has a baby, in the fifth-floor HDB rental flat.
A team of five officials from the Health Sciences Authority went to the flat on Thursday afternoon and took away a bagful of the teenager's clothes at about 3 pm.
Neighbours said they heard sound of breaking glass and arguments from the flat at about 2 am. A neighbour, who gave his name only as Mr Ang, said he was woken up from his sleep by the commotion and he also heard luggage bag being rolled along the common corridor.
Residents said the woman suspect looked troubled and was often seen staring blankly into space.
