The victim, who was 36, was stabbed outside an address in the Hill Street area of Gilford during the early hours of Saturday morning, police said.
He later died from his injuries.
Detectives have named the victim as Eamonn Darren O’Hanlon from north Belfast.
Four people have been arrested and police said all suspects remain in custody.
Witnesses, or anyone with information about the incident, can contact detectives by calling 101, quoting reference 262 21/05/22.