Police were called to reports of the assault in London Road at 12.52pm today (November 27).
A teenage girl was taken to hospital by the London Ambulance Service.
Her injuries are not believed to be life-changing or life-threatening.
A man has been arrested on suspicion of assault and remains in custody.
Investigations continue.
A spokesperson for the Metropolitan Police Service said: “Police were called at 12.52pm on Thursday, November 27 to London Road in Morden following reports of an assault.
“The victim, a teenage girl was taken to hospital by the London Ambulance Service.
“Her injuries are not believed to be life-changing or life-threatening.
“A man has been arrested on suspicion of assault and remains in custody.
“Enquiries remain ongoing.”
