The incident happened in Lower High Street at about 11pm on Friday.
Police say the 22-year-old victim, who was stabbed to his lower back, was taken to hospital and remains there following surgery.
No arrests have yet been made and police are carrying out inquiries.
A West Midlands Police spokesperson, said: "A man was taken to hospital having suffered a serious stab injury in Wednesbury on Friday night.
"It happened in Lower High Street at around 11pm.
"A man aged 22 suffered a stab wound to his lower back and remains in hospital following surgery.
"No-one has been arrested at this stage. CCTV and local enquiries are under way."