Police have said they are likely dealing with a triple homicide investigation after the three men, aged in their 20s or 30s, were pronounced dead at the scene on Elmstead Road.
An investigation is under way and crime scenes are in place in the area as officers begin a full forensic examination.
Chief Superintendent Steve Clayman, commander of the Met's East Area basic command unit, said: "While enquiries into this tragic incident are at an early stage, this is likely to be a triple homicide investigation.
Mayor of London Sadiq Khan said extra police enforcement powers have been authorised for the borough of Redbridge until 8am on Monday following the stabbing attack.
He tweeted: "I'm in touch with senior Met police officers and local representatives after a serious incident in Redbridge tonight, where three men have lost their lives.
"My thoughts are with their families and the local community at this dreadful time."
