The police were called to Paddington Recreation Ground on Monday (June 16) just before 2pm.
Two boys – 15 and 16 – were found with stab wounds and taken to hospital.
Their injuries are not believed to be life-threatening.
A 16-year-old boy has been charged with threatening a person with a bladed article in a public place and wounding with intent.
He was arrested the day after the stabbing and will appear at Highbury Corner Magistrates’ Court on June 19.
A Met Police spokesperson said: “Officers investigating a serious assault in Paddington Recreation Ground, W9 on Monday, 16 June have charged a boy in connection.
“Police were called at around 13:50hrs to reports of two boys – aged 15 and 16- being found with stab injuries.
“Both boys were taken to hospital and their injuries are not believed to be life-changing.
“On Tuesday, 17 June, a 16-year-old boy was arrested in connection with the investigation. He has since been charged with threatening a person with a bladed article in a public place and wounding with intent.
“He will appear at Highbury Corner Magistrates Court on Thursday, 19 June.”
