A 17-year-old boy was shot in the buttocks in Grove Lane, Handsworth - with police called to the scene at around 4.30pm.
The teen was taken to hospital in a stable condition with injuries not thought to be life-threatening.
Detective Inspector Nick Barnes, from our force CID, said: “This is a shocking act of violence on our streets, which is completely unacceptable.
“We’re doing all we can to understand what has happened, why and who was responsible.
“I’d encourage anyone who know anything to get in touch please.”
West Midlands Police has urged anyone with information to get in touch via live chat on their website or by calling 101, quoting log number 2517.
Alternatively Crimestoppers can be contacted anonymously on 0800 555 111.