Police were called to reports of a stabbing at around 6.30 pm on Cortis Road.
In a short statement posted to Twitter, a spokesperson for Wandsworth Met Police confirmed that the victim's condition is not life-threatening.
"Officers investigating the stabbing of a 13yo boy at 6.30pm on Saturday in Cortis Road SW15 have arrested a male."
The 14-year-old male arrested remains in custody.
"Thankfully the victim's physical injuries have been assessed as superficial."
Anyone with information is asked to call the police on 101 quoting reference Cad 6508/12Jun.
To remain anonymous, contact Crimestoppers on 0800 555 111.
