Police were called by London Ambulance Service to reports of an injured man at Alton Street in Poplar just before 2pm on Saturday.
The victim, who had suffered knife injuries, was pronounced dead at the scene around 40 minutes later. A crime scene has been established and Metropolitan Police officers are investigating.
It follows the arrest of 14 people in connection with the three incidents on Friday afternoon and the early hours of Saturday morning.
A pair of teenagers were killed in different parts of London within minutes of each other, while three men were stabbed in a separate attack in the capital hours later.
Emergency services were called out to Wandsworth in south-west London, on Friday evening where the first victim – believed to be in his late teens – was found stabbed. Six males were later arrested and taken to separate west London police stations for questioning.
Within minutes later, armed police were called to reports of a shooting in Plumstead, in the south-east of the capital.
The victim, also believed to be in his late teens, was found with critical injuries. The London Ambulance and the London Air Ambulance attended, but the teenager died at the scene a short while later.
Three men and a woman were later arrested on suspicion of murder and taken to separate south London police stations for questioning.
And in the early hours of Saturday morning, police were called to Clapham, where three men were found with stab and slash injuries. Four men were arrested in connection with the incident.
Scotland Yard said enquiries were underway to notify next of kin in the Alton Street death. A post mortem will be held in due course.
The force said there have been no arrests and officers retain an open mind as to a possible motive.
Anyone who witnessed the incident or has information is asked to contact Tower Hamlets CID on 101 quoting CAD4256/15JUN, tweet @MetCC, or call Crimestoppers anonymously on 0800 555 111.