The boys, aged 13 and 17, were both taken to hospital with stab wounds after the incident in Wednesfield Road, Heath Town, at around 2.15pm on Friday, May 29.
Two ambulances, a paramedic officer and the Midlands Air Ambulance Critical Care Car were sent to the scene of the knife fight.
One of the boys was seriously injured but West Midlands Police said neither of their injuries were believed to be life-threatening.
Both teenagers have now been arrested on suspicion of affray and remain in hospital.
West Midlands Police is continuing to appeal for information.
The incident happened less than 24 hours after a man was shot in the leg in the city and came as the region’s police and crime commissioner warned that shootings and violence are on the rise as gangs "come out of lockdown".
There have been six gun attacks in the West Midlands this week, with a man being left in a critical condition following a shooting at a home in Birmingham last night.