A 21-year-old man was taken to hospital with injuries believed not to be life-threatening after the incident in Wisemore on Sunday.
It happened just before 8.10pm and is believed to have happened following an altercation that started in McDonald’s.
Police confirmed that a 16-year-old boy has been arrested on suspicion of wounding and is in custody for questioning.
A spokeswoman said: “We’ve arrested a teenager after a man was stabbed following disorder in Wisemore, Walsall, just before 8.10pm.
“A 21-year-old man was taken to hospital with injuries which are not life-threatening. Following inquiries a 16-year-old boy has been arrested on suspicion of wounding and is currently in custody for questioning.”
Anyone with information can contact the force via Live Chat on their website and quote 20/629260/22.
McDonald’s has been approached for comment.