Police have arrested three people in connection with the incident.
They were called just before 3am today, Wednesday 11th December, to Bluebell Road after reports a man in his 20s had been stabbed.
He suffered serious injuries and was taken to the Norfolk and Norwich University Hospital, where he remains.
A male and female were arrested after the incident and taken to Wymondham Police Investigation Centre, while another male was taken to Aylsham Police Investigation Centre for questioning.
Two areas in the city have been cordoned off while initial enquiries are carried out.
Anyone with information should contact police on 101, quoting CAD number 34 of 11th December, or call Crimestoppers anonymously on 0800 555 111.