At 5.35pm on Monday (April 23), police officers were called to reports of a stabbing in North End Road.
Two teenagers injured in the incident were airlifted to hospital by London's air ambulance, which had landed nearby in Lillie Road.
Both girls suffered non-life threatening injuries but they remained in hospital on Tuesday morning.
The 17-year-old suspect was arrested at the scene.
North End Road, near The Clarence pub, was taped off for more than an hour while police investigated the crime scene .
The road was reopened shortly before 7pm.
Enquiries into the stabbing continue.