The police were called to an incident at The Broadway in Southall just after 2pm on Saturday (March 15).
The air ambulance, officers and paramedics attended and a 15-year-old boy was taken to hospital after being stabbed.
The injuries are not thought to be life-threatening or changing.
Two 14-year-old boys were then arrested on suspicion of grievous bodily harm with intent soon after.
One has been bailed but the other was charged with wounding with intent.
He will appear at Uxbridge Magistrates’ Court today (March 17).
A Metropolitan Police spokesperson said: “Police were called at 14:06hrs on Saturday, 15 March to a fast food restaurant on The Broadway, Southall following reports of an altercation.
“Officers attended alongside the London Ambulance Service and London’s Air Ambulance.
“A 15-year-old boy was taken to hospital by LAS with stab wounds.
“His condition was later assessed as neither life-threatening nor life-changing.
“Following enquiries in the area, police arrested two boys, both aged 14, shortly afterwards on suspicion of grievous bodily harm with intent.
“They were taken into custody. One has since been bailed pending further enquiries and the other charged.
“The 14-year-old boy from the W12 area will appear at Uxbridge Magistrates’ Court on Monday, 17 March charged with wounding with intent.”